Governor Andrew Cuomo addressed Donald Trump in an open letter after today's shooting in Texas, asking the US president: "When is enough enough?"

He also directed a tweet at Mr Trump in which he wrote: "DO SOMETHING"

The school district has appealed for any photos and video of today's events, presumably to use as evidence during the investigation.

According to an investigative reporter from local television station KHOU, this is the shooting suspect, who police say they have in custody.

Prominent politicians, including top Democrat Nancy Pelosi, have called for action in response to today's shooting.

Former first lady, senator, and presidential candidate Hillary Clinton decried the "national shame" of gun violence and said the US was "failing" its children.

Republican Texas Senator Ted Cruz says he is at the scene of the shooting and is meeting with local law enforcement.

"Any and all federal assets and resources that are needed will be provided," he said in a statement.

"God bless Santa Fe and all who are responding and supporting this community in its time of need." he added.

A high number of police and other emergency service personnel are at the school, whose students were evacuated earlier today.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Officials say the school is an "active crime scene" and that "only first responders and essential personnel" should be there.

Governor Abbott has also said that flags across the state will be flown at half-mast in memory of those who died.

US Education Secretary Betsy DeVos has responded to the incident, saying: "Our nation must come together to keep our students safe."

The suspect in custody has been identified as 17-year-old Dimitrios Pagourtzis, according to CBS News.

David Marshall, chief nursing officer at the University of Texas Medical Branch (UTMB), has told the media that a police officer is in a critical condition and is undergoing surgery.

Another adult and a child are in a stable condition.

The hospital, which is the highest-level trauma centre near the site of the shooting, has called for blood donations.

A reminder of what we know so far about the deadliest school shooting since February's attack in Parkland, Florida:

• Between eight and 10 people, a majority of them students, have been killed at Santa Fe High School in Texas
• One student is in custody and another "person of interest" has been detained
• Explosive devices have been found at the school and the surrounding area
• Police are working to make the devices safe and the public have been warned not to touch suspicious packages

Further to the earlier mention of explosive devices found both on and off the school's campus.

Authorities are warning members of the public to be vigilant and not to touch any suspicious packages.

According to Education Week, external, 12 school shootings have taken place in the US so far in 2018. The number of casualties from today's shooting are not included in this chart.

Donald Trump has spoken with Texas Governor Greg Abbott to offer his condolences for those affected by the shooting at Santa Fe High School.

The president pledged to work with the governor and "provide all appropriate federal assistance", a White House statement said.

Santa Fe Police Chief Jeff Powell confirmed at a news conference that there have been explosive devices found in the high school and in areas near the high school.

Community members should be on the lookout for items that look out of place, he added.

Two Santa Fe High School students describe the immediate aftermath of the mass shooting on their campus.

Scott Taylor, a reporter at ABC 7, says that the high school had had "several active shooting drills" in the past two years.

The governor of Texas says he will speak at the high school at 13:00 local time (18:00 GMT):