Report Confirmed 1 dead, 10 injured in 'horrific terrorist attack' outside London mosque

Good Morning America report, at least 1 person has died and 10 were injured when a van plowed into a crowd gathered outside a London mosque after prayers just past midnight on Monday.

London mayor Sadiq Khan said police were responding to a "horrific terrorist attack."

Prime Minister Theresa May called the attack "every bit as sickening as those that have come before."

"Evil of this kind will never succeed," May said after an emergency meeting at 10 Downing Street to coordinate the government's response.

The Metropolitan Police called the incident a "terrorist attack" and said an investigation was being carried out by the Counter Terrorism Command. “This was an attack on London and all Londoners and we should all stand together against extremists whatever their cause," said Neil Basu, senior national coordinator for counter terrorism.

Some witnesses said there were a total of three "attackers," but police said they arrested a 48-year-old man at the scene on suspicion of attempted murder and that no other suspects had been identified.

"From what we are seeing and from what witnesses have reported to us there was nobody else in the van and it appears at this time that this attacker attacked alone," Basu said.

Two people were treated at the scene and eight were transferred to three London hospitals, according to London Ambulance Service Deputy Director of Operations, Kevin Bate.

The incident happened in Finsbury Park in the north of London, in Seven Sisters Road, according to officials.

May will chair an emergency meeting on Monday morning to coordinate the government's response.

The Muslim Council of Britain called the incident a "terror attack" and the "most violent manifestation" of Islamophobia.

Eyewitnesses interviewed by ABC News said people were gathered outside the mosque after prayers tending to an old man who was having a heart attack when the van drove into them. There were men, old men and women, no children.

Khan called it "a deliberate attack on innocent Londoners, many of whom were finishing prayers during the holy month of Ramadan.

"While this appears to be an attack on a particular community, like the terrible attacks in Manchester, Westminster and London Bridge it is also an assault on all our shared values of tolerance, freedom and respect," Khan said in a statement.

A man identified as Jermain Jackman told the BBC the sidewalks were "packed with people walking home" when the incident occurred.

"It was a van that mounted the pavement as men and women were leaving the mosque to go home to their families and friends and their loved ones," Jackson said.

"During the night, ordinary British citizens were set upon while they were going about their lives, completing their night worship," the Muslim Council said in a statement, adding that "Muslims have endured many incidents of Islamophobia," over the past weeks and months.

"We urge calm as the investigation establishes the full facts, and in these last days of Ramadan, pray for those affected and for justice," the statement concluded.

One person was in custody and the investigation was ongoing, police said.

Britain set its terror at "severe," meaning an attack is highly likely, after a pair of incidents recently.