Dick said: "This was quite clearly an attack on Muslims who looked like they were probably Muslims and they were coming from a prayer meeting".
Imam Mohammed Mahmoud was in the Muslim Welfare House when a van ploughed into worshippers outside.
"Today we come together as we have done before to condemn this act and state an act of hatred of this kind will never succeed in dividing us".
The 47-year-old van driver was pinned down by people at the scene before being detained by police.
Eyewitness Abdul Rahman said the driver said he wanted to "kill all Muslims". 'I want to kill Muslims'.
Saeed Hashi described how he fought with the driver, and how he and two others held him to the ground for 10 minutes as they waited for police to arrive.
He was taken to hospital as a precaution and will undergo a mental health assessment.
London Mayor Sadiq Khan, the first Muslim to serve in that position, said extra police would be deployed.
"While this appears to be an attack on a particular community, like the awful attacks in Manchester, Westminster and London Bridge it is also an assault on all our shared values of tolerance, freedom and respect". "He chose exactly the time that people pray, and the mosque is too small and full, so some pray outside".
The media was also criticized for being slow to call the incident a terror attack.
Witness Cynthia Vanzella told Sky News she was trying to sleep when she heard a lot of noise outside. Police shot and killed the three Islamic extremists who carried out the attack. "One guy caught the guy and brought him down", Bouhllissa told Reuters. "There were bodies around me".
"He was screaming, he was saying, "I'm going to kill all Muslims, I'm going to kill all Muslims".
Another witness, Adil Rana, 24, said, "The van was driving towards us to try and basically hit us at speed".
Dozens of police, fire and ambulance service vehicles have been sent to the area, armed officers are on the scene and a helicopter is overhead.
Mohammed Kozbar said the Muslim community is "in shock".
British security officials, speaking on condition of anonymity in line with official policy, said hate crimes directed at Muslims have increased almost five-fold in the wake of several attacks in Britain.
"Many will feel terrorised, no doubt be angry and saddened, by what has taken place tonight", he added, as he called for calm.
France and Germany also condemned the attack and US President Donald Trump's daughter Ivanka expressed solidarity with the worshippers in a tweet but no comment so far from her father. "We will make sure that we do all we can to reduce these sort of attacks".
Labour leader and local MP Jeremy Corbyn said on Twitter that he was "totally shocked" by the event.
He told the BBC that "an attack on a mosque, an attack on a synagogue, an attack on a church is actually an attack on all of us".
According to Dr. Ahmad, "Terrorism makes him stronger to his faith".