Thousands of people have marched in London to protest against UK intervention in Syria and the airstrikes which have recently been launched. Anti-war activists also demanded a full stop to other UK military campaigns abroad.

Activists and supporters of the Stop the War Coalition gathered outside Broadcasting House at Portland Place before marching to Downing Street.

Slogans like “MPs who voted to kill people #stop bombing Syria”, “Bombing for peace is like f**king for virginity,” and “Syrian lives matter”, were visible on flags and banners carried by the pacifists. The protest closed streets as it weaved along Regent Street, past Piccadilly Circus and Trafalgar Square.

“Stop the war” as well as “Boycott ISIS,” were also seen among the banners in the crowd.

When the rally reached Downing Street several speakers took the stage to condemn the government’s decision to participate in yet another armed conflict, which is the fourth intervention since the anti-terror campaign began in Afghanistan in 2001.

Airstrikes by the UK in Syria were approved by a contentious vote of 397 to 223 in favor of military intervention on December 2.

READ MORE: RAF strikes targets in Syria after parliament votes to bomb ISIS

Opposition Labor Party leader Jeremy Corbyn harshly opposed the move and accused Prime Minster David Cameron of rushing into a war. Corbyn was the chair of the Stop the War Coalition, but resigned a week after his election as leader of the Labour Party in September 2015.

“We say no to the continued violence, we say no to the terror and we say no to the racism that is the fallout of this war,” Nancy Taaffe, from the Socialist Party, told the Daily Mail.

Addressing the crowd outside Downing Street, deputy leader of the Green Party, Shahrar Ali, urged the UK government to accept more Syrian refugees. Some 20,000 Syrian refugees are due to arrive in Britain over the next five years.

“Refugees are not welcome here, according to Cameron. Refugees are welcome here according to us,” Ali was quoted as saying by the Evening Standard.

More than a week after the UK began bombing Islamic State (IS, formerly ISIS/ISIL) in Syria, Michael Fallon, the UK defense secretary, defended his country’s actions in Syria, while at the same time acknowledging the potential danger of increased terrorist threat in the UK.

Thousands here, from all over the country, saying with one clear voice - #StopBombingSyriahttps://t.co/yCk15JMIc8 — Raza Nadim (@razanadim) December 12, 2015

“There will be plots against both our countries as we take the fight to Isil-Daesh,” Fallon said on a visit to the Pentagon. “But we must not allow the idea to take hold that standing up to this terrorism makes our homeland security any worse.”

He also said that UK had had more than doubled the number of missions flown by the RAF to target IS “in its heartland.”