BEIRUT (AP) — Hundreds of Syrians gathered on Monday in a landmark square in Syria’s capital, Damascus, rallying in support of their armed forces, which they say succeeded in confronting the unprecedented joint airstrikes by the West over the weekend.

State TV broadcast the rally live from the central Omayyad Square. Protesters waved Syrian flags at the demonstration, dubbed a “salute to the achievements of the Arab Syrian Army,” set off fireworks and unleashed celebratory gunfire.

Shouts of “Allah, Syria, and only Bashar,” a reference to Syrian President Bashar Assad, rang out.

The joint airstrikes by the United States, Britain and France bombed sites that the three countries said were linked to Syria’s chemical weapons program. The airstrikes were triggered by an alleged chemical attack in the town of Douma, just outside of Damascus.

Syrian activists said more than 40 people were killed but Syria and Russia deny the attack and Russia even accused Britain of staging the attack.

Saturday’s airstrikes came shortly after a fact-finding mission from the Organization of the Prohibition of Chemical Weapons arrived in Syria to investigate. The mission is still expected to make it to Douma, where government security agencies and Russian military police have deployed after the town fell under government control, raising complaints from the Syrian opposition that evidence of chemical weapons’ use might no longer be found.

Faisal Mekdad, Syria’s deputy foreign minister, said Monday that government officials have met with the delegation, which has been in Damascus for three days, a number of times to discuss cooperation.

“Syria stressed during those meetings that it is fully ready to cooperate and to provide necessary facilitations to the delegation to carry out its mission,” Mekdad was quoted as saying by state media.

The OPCW is holding an emergency meeting Monday in The Hague to discuss the suspected chemical attack in Douma.

The strikes have ratcheted up international tension, as the U.S. and Russia exchanged threats of retaliation. U.S. Ambassador to the United Nations Nikki Haley has indicated new economic sanctions will be announced Monday against Russia for enabling Assad’s government to continue using chemical weapons.

Russian President Vladimir Putin said the military strikes violated the U.N. Charter and that if they continue, “it will inevitably entail chaos in international relations,” according to a Kremlin statement on Sunday.

The Syrian government regained full control of Douma on Saturday, following a surrender deal with the rebels who had controlled the town just east of Damascus. It also followed the purported use of chemical weapons there on April 7.

Douma was the last rebel holdout in the eastern Ghouta enclave, which was the target of a government offensive in February and March that killed hundreds and displaced tens of thousands of people.

Syrian media, Russian and Syrian officials have sought to downplay the impact of the joint airstrikes, saying the Syrian air defenses have intercepted most of the missiles. The Pentagon says no missiles were engaged.

Also Monday, British Prime Minister Theresa May was to face angry lawmakers for authorizing the strikes without a vote in Parliament. Her office said she planned to tell them the strikes were “in Britain’s national interest” and were carried out to stop further suffering from chemical weapons attacks.