"We're maintaining that we have a number of options, and all of those options are still on the table. Final decisions haven't been made yet on that front," said the White House Spokesperson Sarah Sanders at a daily briefing on Wednesday afternoon.
Sanders' remarks came hours after U.S. President Donald Trump taunted Russia, saying that missiles "will be coming" to Syria.
"Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and 'smart!'" said Trump in a tweet on Wednesday morning.
Sanders downplayed the possibility of an imminent strike at the briefing, saying that Trump "has not laid out a timetable."
U.S. Defense Secretary Jim Mattis also remained cautious about taking military action against Syria, saying Washington was still "assessing intelligence" about the alleged chemical weapons attack.
"We're still working on this," said Mattis on Wednesday at Pentagon when asked by reporters if there was enough evidence to blame the Syrian government for the deadly attack. ' Activists, local rescuers, and rebels in Syria claim that Syrian government forces used chlorine gas on Saturday in an attack in Douma, a rebel-held area near capital Damascus.
The Syrian Foreign Ministry has denied the accusation, calling rebels' claims "premeditated pretexts."