She told her senior ministers on Thursday the Douma events showed a "deeply concerning" erosion of global legal norms barring the use of chemical weapons.
Cabinet ministers have agreed on a "need to take action" against Syria, following a suspected chemical weapon attack that claimed the lives of dozens of people in the Damascus suburb of Douma.
It also suggested that Prime Minister Theresa May will continue to lead the West's next move together with its "allies", US President Donald Trump and French President Emmanuel Macron.
Theresa May is reportedly adamant that the United Kingdom plays an equal part in any military action against Syria.
"Cabinet agreed that the Assad regime has a track record of the use of chemical weapons and it is highly likely that the regime is responsible for Saturday's attack", a statement from Downing Street said, using the same phrase it deployed following the Sergei Skripal poisoning last month.
The Russian military says that an alleged chemical attack in Syria was staged and directed by Britain.
United Kingdom agrees on 'need to take action' over Syria
Twenty-one percent of the respondents said they did not know if it was necessary to hold a parliamentary vote on whether London should engage in the military actions against Syria. The Downing Street statement did not mention parliament, and a spokeswoman did not comment on those reports.
May is not obliged to win parliament's approval, but a non-binding constitutional convention to do so has been established since a 2003 vote on joining the US -led invasion of Iraq. A YouGov poll showed just one in five members of the public support a strike on Syria.
The Times reports that "the largest U.S. air and naval strike force since the 2003 Iraq war" is now heading towards Syria, and that US-led strikes are expected to begin "within the next three days".
Parliament voted down British military action against Assad's government in 2013, in an embarrassment for May's predecessor, David Cameron.
The war plans of British leaders have been complicated in recent years by the memory of Britain's 2003 decision to invade Iraq after asserting - wrongly, as it later turned out - that President Saddam Hussein possessed weapons of mass destruction.
Wizards guard Jodie Meeks suspended 25 games
The No. 8-seeded Wizards begin their first-round series with the Raptors in Toronto on Saturday. The team went 43-39 this season and suffered 14 losses in their final 21 games.