WASHINGTON: The US Central Intelligence Agency has been feeding information to select rebel fighters in Syria to try to make them more effective against government troops, The Wall Street Journal reported Saturday.

Citing unnamed current and former US officials, the newspaper said the new CIA effort reflected a change in the administration's approach that aims to strengthen secular rebel fighters.

The CIA has sent officers to Turkey to help vet rebels who receive arms shipments from Gulf allies, the report said.

But administration officials cited concerns about some weapons going to Islamists, the paper noted.

In Iraq, the CIA has been directed by the White House to work with elite counterterrorism units to help the Iraqis counter the flow of Al Qaeda-linked fighters across the border with Syria, The Journal said.

According to the report, the West favours fighters aligned with the Free Syrian Army, which supports the Syrian Opposition Coalition political group.

Syrian opposition commanders said the CIA had been working with British, French and Jordanian intelligence services to train rebels in the use of various kinds of weapons, the paper said.

The move comes as the al Nusra Front, the main Al Qaeda-linked group operating in Syria, is deepening its ties to the terrorist organisation's central leadership in Pakistan, The Journal said.

The new aid to rebels doesn't change the US decision against taking direct military action, the paper noted.