Facebook said it wanted to make its social media platform a "hostile environment" for terrorists in a statement issued after attackers killed seven people in London and prompted Prime Minister Theresa May to demand action from internet firms.
Three attackers rammed a rental van into pedestrians on London Bridge and stabbed others nearby on Saturday night in Britain's third major militant attack in recent months.
May responded to the attack by calling for an overhaul of the strategy used to combat extremism, including a demand for greater international regulation of the internet, saying big internet companies were partly responsible for providing extreme ideology the space to develop.
Facebook on Sunday said it condemned the London attacks.
"We want Facebook to be a hostile environment for terrorists," said Simon Milner, Director of Policy at Facebook in an emailed statement.
"Using a combination of technology and human review, we work aggressively to remove terrorist content from our platform as soon as we become aware of it, and if we become aware of an emergency involving imminent harm to someone's safety, we notify law enforcement."
May has previously put pressure on internet firms to take more responsibility for content posted on their services. Last month she pledged, if she wins an upcoming election, to create the power to make firms pay towards the cost of policing the internet with an industry-wide levy.
Twitter also said it was working to tackle the spread of militant propaganda on its platform.
"Terrorist content has no place on Twitter," Nick Pickles, UK head of public policy at Twitter, said in a statement, adding that in the second half of 2016 it had suspended nearly 400,000 accounts.
"We continue to expand the use of technology as part of a systematic approach to removing this type of content.