The US military has sent a task force to Jordan to help it handle an influx of Syrian refugees and prepare for other scenarios, including Damascus losing control of its chemical weapons, a senior US defence official said Wednesday.

A 150-strong force of planners and specialists -- led by a senior US officer -- was looking at ways to prevent the increasingly bloody Syrian civil war from spilling across Jordan's borders, said the official, who was attending NATO talks in Brussels and who asked not to be named.

They are based at an outpost north of the capital Amman and just 35 miles (55 kilometers) from the border, making it the closest US military presence to the Syrian conflict.

The United States says it is providing non-lethal aid to the rebels, refraining so far from providing arms because of fears they could end up in the hands of hardline Islamist groups taking part in the struggle.

US President Barack Obama has however warned of a broader intervention should Syria use or lose control of its chemical weapons arsenal.

A New York Times report said US and Jordanian officials had discussed setting up a humanitarian buffer zone on the Syrian side of the border patrolled by Jordanian forces with US support but are holding off on the idea for now.

Jordan, a longtime US ally, was an early supporter of the rebellion against Syrian President Bashar al-Assad but, along with Washington, fears that the conflict could destabilise an already volatile region.

The Times said the US task force is spending the bulk of its time helping Jordan to coordinate food, water, latrines and other basic services for arriving refugees.

Earlier this month Jordanian riot police used tear gas to disperse Syrian refugees at a camp in the north of the country who set fire to tents and destroyed property in protest at their living conditions.

Jordanian Foreign Minister Nasser Judeh has said that over 200,000 Syrian refugees have crossed into Jordan since the uprising erupted 18 months ago.

UN figures show that over 85,000 refugees are registered in Jordan, with another 36,000 awaiting processing. More than 30,000 refugees are staying in the UN-run Zaatari camp, according to official figures.