Ukraine round-up: Putin watches nuclear tests and a row over a superyacht

President Putin watched the nuclear drills via video link

Russia has carried out its annual nuclear exercises, with its President Vladimir Putin watching them via video link from a big white room at the Kremlin.

His government announced that ballistic and cruise missiles were launched in the Far East and Arctic.

While the US was informed of the drills, they come at a time of heightened tensions with the West over his invasion of Ukraine.

Without providing any evidence, Russia has accused Ukraine of plotting to use a "dirty bomb" - an explosive device mixed with radioactive material. Western countries have widely rejected those allegations as false, and Ukraine has warned that Moscow itself could be preparing such an attack.

Regardless, Russia is standing by its claims.

Read more here:

• How many nuclear weapons does Russia have?

• What is a ‘dirty bomb’ and why is Russia saying Ukraine could use one?

Will Belarus join the war?

Russia and Belarus held joint military drills near the Ukrainian border in February - just days before Russia's full-scale invasion

There are fears that Belarus and Russia could be planning a joint incursion across Ukraine's northern border, after the Kremlin sent thousands of troops to Belarus.

It has prompted a blunt warning from Ukraine -"If the Belarusian army supports Russian aggression, we will respond… with our entire arsenal of weapons."

Belarus shares a border with both Russia and Ukraine, and its authoritarian government, headed by Alexander Lukashenko, is fiercely loyal to the Kremlin.

Belarus is already heavily involved in the war, and is also very dependent on Russia, so if Moscow pressures Minsk to step-up its support - there is not much wiggle room.

Read analysis from Sarah Rainsford, our Eastern European correspondent.

Mercedes pulls out of Russia

Eight months into the war huge companies continue to leave Russia - Mercedes-Benz is the latest.

The German-based luxury vehicle company stopped manufacturing in and exporting to Russia in early March.

But now it says it will withdraw completely from the Russian market and sell shares in its subsidiaries to a local investor.

Ford confirmed on Wednesday that it had finalised a deal to leave Russia too.

Row erupts over superyacht

Meanwhile all the way over in South Africa, a row has erupted over a Russian oligarch's superyacht, which has left Hong Kong and is heading to Cape Town.

South Africa's government insists it will allow The Nord to dock - but Cape Town's mayor says it should be turned away.

The Nord belongs to Alexei Mordashov, an ally of Vladimir Putin who has been sanctioned by the EU and US.

Mayor Geordin Hill-Lewis says he has a "moral duty" to oppose Russia's "unjust war" and has vowed to block the yacht.

But a spokesman for President Cyril Ramaphosa said: "South Africa has no legal obligation to abide by sanctions imposed by the US and EU."

Even if the mayor gets his way - it is not clear how Cape Town officials plan to stop the enormous vessel from docking when it arrives.

War in Ukraine: More coverage

• ANALYSIS: Who is winning the war in Ukraine?

• ON THE GROUND: What weapons are being supplied to Ukraine?

• READ MORE: Full coverage of the crisis