President Pranab Mukherjee and Prime Minister Narendra Modi on Thursday strongly condemned the deadly attack in the heart of London in which five people have been killed and 40 others injured.

"Shocked to hear of (the) terrorist attack in London; condolences to bereaved families and prayers for recovery of injured," the President tweeted.

He said India stood by the United Kingdom and "terrorism must be met through collective action by the international community".

At this difficult moment, India stands with UK in the fight against terrorism. @theresa_may @Number10Gov

— Narendra Modi (@narendramodi) March 23, 2017

Deeply saddened by the terror attack in London. Our thoughts and prayers are with the victims and their families.

— Narendra Modi (@narendramodi) March 23, 2017

Three people and a terrorist were dead after an attacker brought carnage to central London on Wednesday, mowing down pedestrians on Westminster Bridge and hacking at police with knives in the grounds of the Houses of Parliament.

The officer who died in the attack has been named as Keith Palmer, who was 48 and had 15 years service as a police officer.
 

The attacker was shot dead after stabbing Palmer. The other three victims were all civilians, the police officer said.

At least 40 people were hit on the crowded bridge when a 4x4 drove along the pavement, knocking down pedestrians before crashing into a fence below Big Ben, the local media reported.