US National Security Adviser Susan Rice announced in a television interview that Turkey had agreed to let the US and its allies use its bases to conduct activities inside Syria and Iraq.

A US-led military coalition has been bombing fighters from the self-styled “Islamic State” in Iraq and Syria and the discussion continues within the US military whether to join ground combat against the militant extremists in Iraq and Syria.

US Defense Secretary Chuck Hagel’s spokesman said that Hagel had thanked his Turkish counterpart Ismet Yilmaz for Turkey’s “willingness to contribute to coalition efforts, to include hosting and conducting training for Syrian opposition members.”

The Associated Press news agency reported that Turkey authorized the training of up to 4,000 opposition fighters on its soil, once they had been screened by Turkish intelligence agencies.

Pressure on, movement from Ankara

US troops have long operated out of Incirlik Air Base, with roughly 1,500 air force personnel stationed there. The US airstrikes against “IS” are currently reportedly flying out of air bases in the United Arab Emirates, Kuwait and Qatar.

NATO member Turkey had so far refused to get involved in the fighting, calling instead for