U.S military vehicles travel in the northeastern city of Qamishli, Syria, April 29, 2017. (Xinhua/REUTERS)

WASHINGTON, April 4 (Xinhua) -- The White House said on Wednesday that there was no fixed departure date for the U.S. troops in Syria, although the U.S. president more than once expressed eagerness for a quick military withdrawal from the war-torn country.

President Donald Trump was "not going to put an arbitrary timeline. He is measuring it in actually winning the battle, not just putting some random number out there," said the White House Press Secretary Sarah Sanders at a daily briefing on Wednesday afternoon.

Over the past week, Trump has reiterated his intention of bringing American troops back from Syria, claiming that the costly U.S. military presence in the Middle East has brought "nothing, except death and destruction."

Meanwhile, the Pentagon and the U.S. State Department have voiced concern that a much longer-term effort was necessary to fully defeat the militant group of the Islamic State (IS).

A member of U.S forces rides on a military vehicle in the town of Darbasiya next to the Turkish border, Syria, April 28, 2017. (Xinhua/REUTERS)

"The goal again is to defeat ISIS (IS)," said Sanders. "And when there's no longer a need for troops to be there and we can transition to that local enforcement, that (the troop withdrawal) certainly would be the objective," adding that the focus of the United States was to eradicate any chance of the re-emergence of the IS.

Sanders also pressured the U.S. allies in the region, saying that they should "put more skin into the game."

In this handout photo provided by the U.S. Navy, U.S. navy guided-missile destroyer USS Porter fires a tomahawk land attack missile in the Mediterranean Sea, April 7, 2017. A total of 59 Tomahawk Land Attack missiles were launched from the destroyers USS Porter and USS Ross in the Eastern Mediterranean Sea at about 8:40 p.m. EDT on April 6 (4:40 a.m. on Friday in Syria), and Syrian aircraft, hardened aircraft shelters, fuel points, air defense systems, and radars were targeted, according to a Pentagon statement. (Xinhua/U.S. Navy)

The United States has been aiding a military campaign in Syria which had taken back much of the territory once occupied by the militant group.

There are around 2,000 U.S. troops stationed in Syria so far.