The Republican-led U.S. Senate backed largely symbolic legislation on Monday that broke with President Donald Trump by opposing plans for any abrupt withdrawal of troops from Syria and Afghanistan.
It acknowledged progress against Islamic State and al Qaeda in Syria and Afghanistan but warned that "a precipitous withdrawal" could destabilise the region and create a vacuum that could be filled by Iran or Russian Federation.
Many members of Congress, including several fellow Republicans, strongly disagree with a plan Trump announced in December to withdraw 2,000 US troops from Syria on the grounds that the militant group no longer posed a threat.
U.S. officials tell Reuters that the military has already started the withdrawal process, adding hundreds of troops to Syria to facilitate a safe pullout.
President Donald Trump's abrupt decision to withdraw American troops from Syria shocked American military officials and US allies alike. In general, he said officials were "aware that he had expressed a desire and intent in the past to depart Iraq, depart Syria".
"I was not consulted", he added.
The top commander of U.S. forces in West Asia, General Joseph Votel, told a Senate committee on Tuesday that of the 34,000 square miles (88,060 square kilometres) of territory that Islamic State once held, it now controls less than 20 square miles (51.7 square kilometres).
FILE PHOTO: U.S. President Donald Trump talks to reporters about the killing of journalist Jamal Khashoggi in Turkey during a bill signing ceremony at the White House in Washington, U.S., October 23, 2018.
Trump was severely criticized by American politicians for his decision to withdraw troops from Syrian territory, while some versions of the reason for the measure were discussed.
Last week, U.S. intelligence chiefs also broke with the president, saying Islamic State would continue to pursue attacks from Syria, as well as Iraq, against regional and Western adversaries, including the United States.
U.S. officials in recent weeks say Islamic State has lost 99.5 percent of its territory and is holding on to fewer than 10 square kilometres of turf in Syria - an area smaller than New York's Central Park.
The Pentagon's own internal watchdog released a report on Monday saying Islamic State remained an active insurgent group and was regenerating functions and capabilities more quickly in Iraq than in Syria.
Trump himself is expected to speak to the gathered foreign ministers at the State Department-hosted conference on Wednesday is widely expected to reiterate and expand on his anti-Islamic State message from the State of the Union, officials said.