"Here we go!" - US President Donald Trump reacts to Russia's drone incursion over Poland, saying Moscow violated its airspace
Russia's defence ministry says it did not plan to attack any targets in Poland
Poland's Prime Minister Donald Tusk says up to four of 19 Russian drones were shot down by Polish and Nato aircraft - BBC Verify delves deeper
It marks the first time Russian drones have been downed over the territory of a Nato country
Tusk also warns that Poland is at its closest to open conflict since World War Two
Meanwhile, the UK's defence minister says he has asked Britain's armed forces to "look at options to bolster" Nato's air defence over Poland
The drones that entered Poland were part of overnight attacks on Ukraine, during which Russia launched 415 drones
Tusk: Poland closest to open conflict since World War Two, warns PM
In Ukraine, Russian strikes continue across the country, with regular alerts over the last few hours.
The Ukrainian armed forces warns civilians of incoming drones and cruise missiles.
The alerts are being posted every few minutes, reflecting the escalating aggression, with constant reminders for residents to seek shelter if in areas under attack.
Poland's major air hub, Warsaw's Chopin International Airport, has just issued a statement saying there are no flight operations for the time being.
"The airport remains open, but no flight operations are currently taking place," it says in a statement on X.
It adds that passengers should follow government announcements and airline updates.
Sarah Rainsford
Eastern Europe correspondent, reporting from Kyiv
The latest drone incursion from Russia into Polish airspace comes just days after Moscow's forces mounted serious aerial attacks against Ukraine - right at the heart of the capital.
In Kyiv, a key government building was hit by a Russian missile in the early hours of Sunday morning. That's the first time a Ukrainian government building has been hit.
I reported from inside the building shortly after that attack:
Inside Kyiv government building hit by missile strike
In the eastern Donbas region, more than 20 civilians were killed by a Russian glide bomb on Tuesday as they queued to collect their pensions.
President Volodymyr Zelensky condemned the strike on the village of Yarova as "savage" and called once again on Ukraine's allies to increase the pressure on Moscow through sanctions.
Read more of my report on Russia's deadlier attacks.
With the Polish armed forces confirming objects have been "downed", it marks what could be the first time the Nato country has directly engaged Russian assets in its airspace since Russia's full-scale invasion of Ukraine in 2022, if the objects are confirmed to be Russian.
It's not the first time Polish fighter jets have been deployed since the conflict began. But previous instances mostly concerned Russian drones overflying Polish airspace trying to reach Ukraine.
Russia has so far been muted about the incident. President Vladimir Putin has repeatedly denied any intention to wage war against Nato countries - which many Western officials are convinced is contrary to their assessment.
We have just received a further update from Defence Minister Władysław Kosiniak-Kamysz.
According to the minister, Poland's Territorial Defence Forces have been activated for "ground searches of downed drones".
According to the government, the forces constitute an "integral part" of Poland’s defence and deterrence potential.
In a post to X, Kosiniak-Kamysz also warned people not to pick up any "fragments of objects", saying they should instead inform the police.
Image source, ReutersPolish Prime Minister Donald Tusk is "present at the scene of the operations", Deputy Defence Minister Cezary Tomczyk says in a post on X.
Earlier Tusk said on social media that the Polish military forces "deployed weapons against the objects" - referring to what the military calls Russia's "drone-type" objects.
Tusk also said he received a direct report from the operational commander.
We will bring you more updates when we have further updates from the PM.
The army's operational command has listed three regions that are most vulnerable right now: Podlaskie, Mazowieckie, and Lublin Voivodeships.
These regions are all located in the eastern part of the country and border Belarus and Ukraine.
Poland's capital, Warsaw, is situated in the centre of Mazowieckie.
The armed forces adds that it is monitoring the situation, and that its subordinate forces and resources "remain fully prepared for immediate response".
Katy Watson
Every night, Ukrainians brace themselves for air attacks from Russian drones and missiles. Some nights are worse than others - but Ukraine never escapes the aggression. The air raid sirens that ring out across cities are the soundtrack to most Ukrainians’ lives now.
And every morning, the Ukrainian military release the numbers – how many drones and missiles attacked, where they hit – and who got hurt. It’s a familiar pattern but the air assaults are getting more brazen.
Earlier this week saw the biggest-ever air assault on Ukraine, with more than 800 drones. A government building was targeted.
Image source, ReutersNow, drones have been flown to the far west of Ukraine - not the first time this part of the country has been hit, but the frequency is increasing.
Just a few weeks ago when I was in Ukraine, Polish fighter jets were scrambled because of drones close to the border.
Now Warsaw's airport has been shut, it's a clear sign of the escalation and the panic as Iranian-made Shahed drones infringe on Polish airspace.
Those talks between Donald Trump and Vladimir Putin in Alaska - not even four weeks ago - feel like a lifetime away. So too does the prospect of peace.
Polish Prime Minister Donald Tusk has said an operation is under way "related to multiple violations of Polish airspace".
In a post on X, the PM says he's been in "constant contact" with the Ministry of Defence, and has received a direct report from the operational commander.
The Polish Armed Forces said they have deployed weapons to neutralise drone-type objects that "repeatedly violated" their airspace this morning.
"Weapons have been used, and operations are under way to locate the downed objects," it said in an earlier post on X.
Image source, Getty ImagesAn operation to "neutralise" objects that violated Poland's airspace is under way, the country's Deputy Defence Minister Cezary Tomczyk says.
"Over Poland, an operation to neutralise objects that have violated and exceeded the border of the Republic of Poland is under way," Tomczyk posted on X.
"All services are in action. We ask you to follow the announcements of the Polish army and the police."
We can now bring you more updates from the Polish Armed Forces.
They have just confirmed that the country's airspace was "repeatedly violated by drone-type objects" during Russia's strikes in Ukraine.
The army's operational command also says in a post on X that an operation is under way to "identify and neutralise the targets".
The Polish army has just made a statement, calling the military operation "ongoing".
It also urged everyone to stay home, according to the Reuters news agency.
The Polish armed forces has posted an update on X, saying it scrambled its aircraft to safeguard its airspace.
"Polish and allied aircraft are operating in our airspace, while ground-based air defence and radar reconnaissance systems have been brought to the highest state of readiness," the operational command of the Polish armed forces posted.
Senator Chris Murphy, the top Democrat on the Senate Foreign Relations Committee, said that it would "be incredibly serious" if the reports of Russian "aerial assets flying over a Nato country" are true.
Murphy, however, also acknowledged that Poland has multiple times been caught in the crossfires of this ongoing war due to its proximity to Ukraine.
Joel Wilson, Representative for South Carolina from the Republican Party, who also sits on Foreign Services and Armed Services, called Russia's alleged actions an "act of war".
"I urge President Trump to respond with mandatory sanctions that will bankrupt the Russian war machine and arm Ukraine with weapons capable of striking Russia," he wrote in a post on X, highlighting that the latest development happened days after Trump hosted Polish President Nawrocki at the White House.
Four airports in Poland, including its largest one in Warsaw, have closed after reports Russian drones entered its airspace, according to the Reuters news agency.
Two airports in the capital Warsaw - the major hub Chopin Airport and Warsaw Modlin Airport - were closed. Also suspended were Rzeszów-Jasionka Airport - which is the air hub closest Ukraine - and Lublin Airport according to a notice posted to the US Federal Aviation Administration's website.
This comes as Nato and Polish fighter jets were scrambled as Russia launched another massive attack on Ukrainian regions close to the border with Poland.
Stay with us as we bring you the latest updates.