The US will send 250 additional military personnel to Syria to support local militias in the fight against ISIS, officials have said.
The goal, they say, is to encourage more Sunni Arabs to join Kurdish fighters in north-eastern Syria.
The new deployment will bring to 300 the number of US forces in non-combat roles in Syria.
Most of the additional personnel will be special operation forces, the AP reports. The group will also include medical and logistical troops, it adds.
A formal announcement is expected from President Barack Obama during his visit to Hannover on April 25, where he will discuss Syria and other foreign policy issues with leaders of the UK, Germany, France and Italy.
Barack Obama has resisted calls to send US troops into Syria, where a five-year-old conflict has killed more than 250,000 people and displaced some 11 million others.isis
Of those, four million have fled abroad, including growing numbers who are making the dangerous journey to Europe.
The crisis has put pressure on leaders there, who are struggling to halt a massive influx of migrants and refugees.
Speaking alongside Barack Obama, German Chancellor Angela Merkel on April 24 urged warring parties to set up safe zones in Syria where refugees would be protected within the country.
Angela Merkel expressed hope that such a plan might eventually be agreed at peace talks taking place in Geneva.
Barack Obama, however, said it would be “very difficult” for those zones to work without a large military commitment.
ISIS has lost parts of the territory it once controlled in Syria. Most recently, they were pushed back by Russian-backed Syrian forces from the strategic city of Palmyra.
The group has also had significant setbacks in Iraq, including the loss of Ramadi, the capital of Anbar province.
The US has led a coalition against the militant group in both Syria and Iraq.
US troops have been deployed to Iraq to assist the Iraqi army in combating a growing Sunni militant insurgency, the Pentagon has announced.
Nearly half the 300 special operations soldiers promised by President Barack Obama are in Baghdad or on the front lines of the fight.
The rest are expected within days.
Meanwhile, US Secretary of State John Kerry called for regional unity to expel the Sunni ISIS rebels who have taken large swathes of Iraq.
On Tuesday, two teams totaling 40 US troops began work assessing Iraqi troops on the front line, the Pentagon said.
US troops have been deployed to Iraq to assist the Iraqi army in combating a growing Sunni militant insurgency (photo NBC News)
An additional 90 personnel will work in Baghdad to set up a new joint operations command centre.
Those teams will be joined by an additional four teams of 50 troops each in the next few days.
The Obama administration has stressed the troops are not intended as operational forces but instead are there to advise the Iraqis and provide intelligence.
The Iraqi government had requested American air strikes, but Barack Obama has been reluctant to do anything that could lead to accusations the US was taking sides in a sectarian conflict.
The insurgents, spearheaded by Islamists fighting under the banner of the Islamic State of Iraq and the Levant (ISIS), have overrun much of north and west Iraq, including the second-biggest city, Mosul.
The violence has claimed at least 1,075 lives in Iraq in June alone, most of them civilians, a UN human rights team has reported.
The UN said the figures, which include a number of verified summary executions, should be viewed as an absolute minimum.
President Barack Obama has announced that the US will keep 9,800 troops in Afghanistan after it concludes its combat mission at the end of this year.
Under the plan Barack Obama announced at the White House, the US will continue to withdraw troops until only a small residual force remains after 2016.
The remaining troops would guard the US embassy, train Afghan forces and support counter-terrorism operations.
But the plan depends on the Afghans signing a joint security agreement.
President Barack Obama has announced that the US will keep 9,800 troops in Afghanistan after it concludes its combat mission at the end of this year (photo AP)
While current Afghan President Hamid Karzai has refused to sign such an agreement, the Obama administration appears to be confident either of the two candidates seeking to replace him would do so.
“This year, we will bring America’s longest war to its responsible end,” Barack Obama said.
The troop numbers Barack Obama announced are largely in line with what military commanders have been asking for. His announcement indicates the longest war in American history – launched by President George W. Bush following the 11 September 2001 terror attacks – will end by the time he leaves office.
He confirmed the US would seek to have 9,800 troops across Afghanistan at the beginning of 2015, but that number would be reduced by about half by the end of the year and would be concentrated in Kabul and at Bagram Air Force Base.
“We will no longer patrol Afghan cities and towns, mountains or valleys,” Barack Obama said.
“That is a task for the Afghan people.”
By 2016, Barack Obama said, the military will draw down to a “normal embassy presence” with an additional security detail, “just as we’ve done in Iraq”.
“We have to recognize Afghanistan will not be a perfect place – and it is not America’s responsibly to make it one,” Barack Obama said.
However, he added the US would help Afghans secure a “hard-earned peace”.
Afghanistan’s run-off election between Abdullah Abdullah and Ashraf Ghani to replace Hamid Karzai is set for 14 June.
Barack Obama noted on Tuesday that both have said they would sign a security agreement with the US.