Almost 1,000 U.S. troops are in Syria as part of the ongoing preparation for the fight to oust the Islamic State group from its self-declared headquarters of Raqqa. Around 500 soldiers were deployed into Syria with heavy artillery guns, senior U.S. official said Wednesday. According to the Pentagon, an additional "400 or so" Marines and Army Rangers have arrived in the last few days.

The deployment is temporary, said Coalition spokesman U.S. Air Force Colonel John Dorrian, and the additional forces were sent to Manbij in the coutnry's north in order to create "reassurance."

The forces would be working with local partners in Syria – the Syrian Democratic Forces and the Syrian Arab Coalition – and would not have a frontline role, he said.

Dorrian added that the campaign to isolate Raqqa is "going very very well."

The deployment is likely an early indication that the White House is leaning toward giving the Pentagon greater flexibility to make routine combat decisions in the ISIS fight. Military commanders frustrated by what they considered micromanagement under the previous administration have argued for greater freedom to make daily decisions on how best to fight the enemy.

Open gallery view Turkey's Chief of Staff General Hulusi Akar meets with U.S. Chairman of the Joint Chiefs of Staff Joseph Dunford in Antalya, Turkey, March 7, 2017. Credit: HANDOUT/REUTERS

The news came on the same day that the top U.S. military officer, Marine General Joseph Dunford, met his Turkish counterpart in the southern Turkish province of Antalya, Reuters reported.

A U.S. defense official, speaking on condition of anonymity with Reuters, said Dunford did not inform his Turkish counterpart of any decision about the Raqqa offensive, in remarks that appeared at odds with the Turkish account.

The Marines moving into Syria are pre-positioning howitzers to be ready to assist local Syrian forces, said the official, who was not authorized to discuss the deployment publicly so spoke on condition of anonymity.

In addition, the U.S. is preparing to send hundreds of U.S. troops to Kuwait in order to be ready to join the Islamic State fight if they are needed, the official said. The number would be fewer than 1,000, the official said.

The latest troop movements come on the heels of the recent temporary deployment of some dozens of Army forces to the outskirts of Manbij, Syria, in what the Pentagon called a "reassure and deter" mission. Flying American flags and moving in large, heavily armored vehicles, the troops were there to keep a lid on tensions in the area, the Pentagon said.

It appeared the forces were largely there to insure that Turkish fighters and Syrian opposition groups focused on battling ISIS rather than each other.

Under the existing limits put in place by the Obama administration, the military can have up to 503 U.S. forces in Syria. But temporary personnel do not count against the cap. The movement of the Marines to Syria was first reported by The Washington Post.

Trump has made defeating Islamic State one of the key goals of his presidency, but had campaigned on a strict anti-war platform, calling U.S. involvement in Iraq 'one of the worst decisions in history' and vowing no more 'stupid wars.'

Pentagon leaders sent a new plan to defeat ISIS to the White House late last month. It outlined a strategy that would likely increase the number of U.S. troops in Syria in order to better advise and enable the U.S.-backed Syrian fighters who will take on the battle for Raqqa.

The military has mapped out a series of options for the Syria fight, including increased artillery support, more Apache helicopters and a more robust training campaign.

U.S. officials say the battle for Raqqa will look much like the fight in neighboring Iraq, where local forces are in a fierce battle to retake the northern city of Mosul from ISIS. As troops were preparing to move into Mosul, the U.S. set up bases outside the city to use as logistical hubs and as locations for heavy artillery.

The moves to pre-position U.S. troops closer to the fight, so they can be tapped as needed, are the kinds of decisions that military commanders say they need to be able to make more quickly, without going to the White House every time for approval.