United Nations inspectors have returned to The Hague in the Netherlands to begin the process of analyzing evidence collected in a fact-finding mission to Syria regarding the use of chemical weapons in the Ghouta region of Damascus.

U.N. representative Martin Nesirky told reporters at a press briefing on Saturday that the U.N. mission is “uniquely capable of establishing, in an impartial and credible manner, the facts of any use of chemical weapons based directly on evidence collected from the ground.”

Just hours ago, U.S. President Barack Obama announced at the White House that the U.S. would take military action against the Syrian regime in retaliation for the Aug. 21 chemical-weapons attack that reportedly killed 1,429 people, including more than 400 children.

Meanwhile, the U.N.’s 13-member team is “spending the day collating the samples and other evidence which they have prior to the testing in the laboratories in Europe,” Nesirky said.

Angela Kane, the High Representative for Disarmament Affairs, has briefed U.N. Secretary General Ban Ki-moon on the investigation. She was a member of the team in Damascus.

While Nesirky declined to give a timeline for their final report, he did indicate that Ban has requested that the investigation be expedited. “Whatever can be done to speed up the process is being done,” Nesirky said. “The aim of the game here, the mandate, is very clear, and that is to ascertain whether chemical weapons were used, and not by whom,” he added.

Both Syrian President Bashar Assad’s government forces and the rebel opposition have been accused of being behind the chemical-weapons attack.

Nesirky rebuffed suggestions that the U.N. team left Syria to make room for the impending U.S. military strike. “I have seen all kinds of reporting suggesting that the departure of the chemical-weapons team somehow opens a window for military action of some kind,” he said. “Frankly, that is grotesque, and it’s an affront to the more than 1,000 staff, U.N. staff, who are on the ground in Syria delivering humanitarian aid and who will continue to deliver critical aid.”

This time around, the U.S. won’t be counting on the U.K. as a close ally. This week, the British Parliament voted not to take part in any military action in Syria, despite the best efforts of Prime Minister David Cameron to convince its members otherwise.

Meanwhile, France remains steadfast in pledging support for the U.S. strike. Obama spoke to French President Francois Hollande just after his announcement in the Rose Garden. “The two leaders agreed that the international community must deliver a resolute message to the Assad regime -- and others who would consider using chemical weapons -- that these crimes are unacceptable and those who violate this international norm will be held accountable by the world,” the White House said of the conversation, according to the Wall Street Journal.

Hollande is facing pressure to put the question of supporting a military strike in Syria to a vote before the French Parliament. “Like the U.S. president, who decided to consult the U.S. Congress in the name of democratic principles, the French president must organize, after the debate, a formal vote in parliament,” said Jean-Louis Borloo, leader of the French opposition Union of Democrats and Independents, or UDI, according to Reuters.

Obama said he would seek congressional authorization for a military strike against Syria once Congress returns from recess Sept. 9.