Updated 12:10 p.m.
United Nations chemical weapons investigators said they were shot at while en route to inspect a site where chemical weapons were suspected of being used Aug. 21 in the killing of hundreds of civilians.
A U.N. vehicle was shot at multiple times by "an unknown sniper," UN Secretary General Ban Ki-moon said Monday. After replacing the attacked vehicle, the UN team was able to make it to the site where they interviewed witnesses, survivors, and doctors, and collected samples, he said.
He said that he had instructed Angela Kane, the UN's under-secretary for disarmament who is overseeing the investigation, "to register a strong complaint to the Syrian Government and authorities of opposition forces so that this will never happen and the safety and security of the investigation teams will be secured from tomorrow."
President Obama met with his national security team Saturday as the United States weighs its response to the reports of chemical weapon use.
"We have a range of options available, and we are going to act very deliberately so that we’re making decisions consistent with our national interest as well as our assessment of what can advance our objectives in Syria,” a White House statement said Saturday.
The Syrian government led by President Bashar al-Assad agreed to allow the inspectors in on Sunday after UN pressure to do so.
Sen. Bob Corker, the ranking Republican on the Senate Foreign Relations Committee, said he spoke with administration officials in the situation room Sunday night and that they are working to build a coalition of NATO allies.
The U.S. will strike against the Assad regime, Corker said on Monday’s Morning Joe.
“Response is imminent” the Tennessee Republican said. “I don’t think there’s any question in our administration’s mind that chemical warfare has been used…I think you’re going to see a surgical, proportional strike against the Assad regime for what they have done and I support that.”
NBC News’ Andrea Mitchell said the response wouldn't happen in the next day or two, but soon.
"I'm told it’s not imminent, but it’s moving very quickly," she said. "We’re still working with Congress and the allies.”
Corker shied away from the idea of an involved strike or providing rebels with aircraft assistance.
“I do not want us though to move into a situation where we’re moving beyond supporting the moderate, vetted opposition,” he said. “ I think Syrians need to be the ones to take care of this.”
Corker repeatedly said he hopes the president will go to Congress for authorization of the strike, but admitted that he doesn’t actually need Congress’ stamp of approval.
“They do not need an authorization, but I do hope they’ll come for one,” Corker said, acknowledging that Congress is on recess at present. "They can start, but hopefully Congress will take up an authorization for this [once they are back in session]."
An authorization of a surgical strike, he said, is “the right thing, that’s what the American people expect their legislators to do.”