WASHINGTON - The US military is mulling about leaving up to 1,000 troops in Syria, further drifting away from President Donald Trump's original plan of a total withdrawal, said US media on Sunday.

The troops will be deployed from northern Syria to the south, continuing to work with Kurdish fighters, reported the Wall Street Journal, citing anonymous administration officials.

The US officials said the number of Western troops to be left in Syria is still to be decided.

Meanwhile, Washington plans to withdraw hundreds of American forces when "the last bastion of Islamic State is seized," a move that will be in accord with Trump's original plan, according to the report.

On Feb 21, the White House announced that the United States would leave about 200 troops in Syria after the planned pullout. Trump confirmed the next day that a small fraction of US forces would remain in Syria with troops from other countries.

Citing a senior administration official, US media later reported that the US military would leave about 400 troops in two different regions of Syria.

Currently, there are about 2,000 US troops in Syria.

Declaring victory over the Islamic State, Trump last December announced the withdrawal of US troops from Syria, leading to the resignation of then US Secretary of Defense James Mattis.