By Louis Charbonneau and Edith Honan
UNITED NATIONS (Reuters) - The United Nations on Saturday vehemently rejected suggestions that the world body was somehow stepping aside to allow U.S. air strikes on Syria over an alleged chemical attack, saying its humanitarian work in the conflict-ravaged nation would continue.
"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," U.N. spokesman Martin Nesirky told reporters.
"Frankly, that's grotesque, and it's also 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," he said.
U.N. experts arrived in the Netherlands on Saturday with evidence gathered in their investigation of a poison gas attack in Syria. Also on Saturday, President Barack Obama said he had decided the United States should strike Syrian government targets, but that he would seek a congressional vote for any military action.
Nesirky repeated that the inspectors would return later to investigate several other alleged poison gas attacks that have taken place in Syria during the country's 2-1/2-year civil war.
He also responded to U.S. Secretary of State John Kerry's remarks on Friday that the U.N. chemical weapons experts cannot provide any information that the United States, which blames Syrian President Bashar al-Assad for last week's attack that Washington says killed more than 1,400 people, does not already have.
"The United Nations 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 on the ground," he said.
Assad's government, like Russia, blames the rebels for last week's alleged chemical weapon attack.
U.N. diplomats told Reuters on Friday that U.N. Secretary-General Ban Ki-moon explained to delegates from the five permanent Security Council members - Britain, China, France, Russia and the United States - that it would take up to two weeks before the chemical inspectors' final report is ready.
NO CHANGE IN INSPECTORS' MANDATE
U.N. officials say the world body's findings will be important because they will be widely seen as irrefutable, in contrast to doubts that arise with intelligence in light of the erroneous information on Iraq's weapons of mass destruction programs that was used to justify the 2003 invasion.
Nesirky was also asked about the legality of any military action against Syria without authorization of the Security Council. He responded by saying: "The secretary-general has underscored the importance of the U.N. charter."
According to the U.N. charter, the council should authorize any military action that does not involve self-defense.
Obama said on Saturday he was "comfortable going forward without the approval of a United Nations Security Council that so far has been completely paralyzed and unwilling to hold Assad accountable."
"While the U.N. investigation has some time to report on its findings, we will insist that an atrocity committed with chemical weapons is not simply investigated," he said. "It must be confronted."
Russia, backed by China, has used its veto power in the Security Council three times to block resolutions condemning Assad's government and threatening it with sanctions.
The United States has bypassed the United Nations in the past when the council was deadlocked, such as in the case of the Kosovo war in 1999. At that time, Washington relied on NATO authorization for its bombing campaign.
The U.N. inspectors will determine only whether chemical weapons were used last week and in several other alleged poison gas attacks, not who used them. Nesirky was asked why the United Nations does not expand the mandate to include naming those responsible for any chemical attacks.
"The mandate is the mandate. The team and the secretary-general will abide by that mandate," he said. "The mandate is robust and provides for the United Nations to be able to provide for, in an impartial and credible manner, a picture of what happened."
He added that the mandate was derived from a U.N. General Assembly resolution.
"Let's not forget that these are scientists, technical and medical experts who braved sniper fire to go to collect samples and to interview witnesses and survivors," he said.
The United Nations has received at least 14 reports of possible chemical weapons use in Syria. After months of diplomatic wrangling, the U.N. experts, led by Swedish scientist Ake Sellstrom, arrived in Syria on August 18 with a 14-day mandate to visit the country.
The U.N. team was initially going to look into three incidents, but its priority became last week's attack. The inspectors have also been looking into Syrian allegations that the rebels used chemical weapons three times this month against the Syrian army - allegations that Washington has dismissed.
Diplomats said there was a possibility that Russia, which opposed military action against Syria, would call for an emergency Security Council meeting. But so far the Russian delegation has made no move to demand that the 15-nation body meet, the envoys told Reuters on Saturday.
The upcoming Group of 20 nations summit in St. Petersburg, Russia on September 5-6 would be a good opportunity for Ban, who will be attending, to discuss the Syrian crisis with world leaders, Nesirky said.
(Editing by Jackie Frank and Vicki Allen)