The warning comes after reports the administration is considering new military options.
The senior military aide to the defense secretary had been dismissed from his position.
Special Forces Staff Sgt. Adam S. Thomas was 31.
The Iran Sanctions Act expires at the end of the year.
"Pence last night was brilliant in attacking Trump's policy on Russia," McFaul tweeted.
Sen. Mike Lee said a military escalation in Syria would require congressional approval.
Lawmakers want to know how the VA has improved the hotline, after reports that calls were going to...
"The U.S. and its coalition partners must issue an ultimatum to Mr. Assad," he said.
OPINION | There's no reason they can't meet their defense spending obligations.
Military strikes against the Assad regime are reportedly among the options.
Annual joint military exercises by the United States and the Philippines got underway Tuesday with...
Kerry said the Kremlin made a “profoundly ill-advised decision” to stick by Assad.
He said foreign adversaries will want to test the new administration.
The Obama administration had fought to block the depositions.
Sunni militia officers said at least 19 people were killed.
“There should be consequences for Russia’s actions," said Sen. Ben Cardin (D-Md.).
A majority of Chinese citizens see the U.S. as a bigger threat than ISIS.
J Street says Sens. Toomey and Johnson are "wrong" like Donald Trump on the agreement.
Experts analyzed commercial satellite imagery and found craters associated with airstrikes.
The service member, who has yet to be identified, was killed by a roadside bomb.
The case could have exposed internal administration talks about arming Libyan rebels.
The service member was killed by a roadside bomb while on patrol.
Russia said the missile system will defend its naval base and ships.
The controversial proposal garnered a record 174,411 responses.