RAQQA, Syria (Reuters) - Kurdish-allied Syrian Arab militias are redeploying 1,700 fighters from fronts against Islamic State to the Afrin region to help fend off a Turkish offensive, they said on Tuesday.

“We have taken out around 1,700 fighters ... to defend Afrin against terrorism,” said Abu Omar al-Edilbi, the spokesman for the militias, which have been fighting in eastern Syria as part of the U.S.-backed Syrian Democratic Forces (SDF).

After announcing the redeployment, he told Reuters in Raqqa that 700 of the fighters had already gone to Afrin in northwest Syria. They were moving from frontlines further east, where the Kurdish-led SDF seized vast territory from Islamic State militants last year with the help of U.S. jets and special forces.

“We are (originally) from Aleppo and Idlib...,” he said. “We had to because our families were homeless and displaced to Afrin more than three years ago... We had to (redeploy fighters) unfortunately and we informed our leadership that we must pull our forces.”

The Pentagon said on Monday that Turkey’s offensive against U.S.-backed forces in Syria had affected the fight against Islamic State and led to an “operational pause” in the east.

Pentagon spokesman Colonel Robert Manning said some SDF ground operations had temporarily halted.

The SDF alliance, with the Syrian Kurdish YPG militia at its forefront, has not disclosed any numbers of fighters moving to Afrin in recent weeks.

Turkey launched its air and ground assault on Afrin in January to drive out the YPG, which it sees as terrorists with links to a Kurdish insurgency at home.

YPG spokesman Nouri Mahmoud said there were around 10,000 fighters in the Afrin region long before the Turkish operation started. “The numbers in Afrin are not a problem,” he said. “The problem is the aircraft bombing the villages.”

Turkey has said that a U.N. Security Council resolution demanding a 30-day ceasefire across Syria does not apply to the YPG and has rejected Western calls to implement the truce in Afrin.

U.S. support for the Kurdish forces in Syria has infuriated Ankara, which views the YPG as an extension of the outlawed Kurdistan Workers Party (PKK) that has waged a decades-long insurgency on Turkish soil.