A man waves as Turkish armored vehicles escort members of the Turkish-backed Free Syrian Army, a militant group active in parts of northwest Syria, as they cross the Turkey-Syria border on Thursday, in Akcakale, Turkey. Photo: AFP

Turkey on Thursday angrily rejected international criticism of its attack on a Kurdish militia in Syria, reporting ­progress by its forces on the second day of an operation that world powers fear could further destabilize a region in turmoil.

Taking aim at the EU and Arab powers Saudi Arabia and Egypt, which have voiced opposition to the operation, Turkish President Tayip Erdogan said those objecting to Turkey's actions were "not honest." He threatened to permit Syrian refugees in Turkey to move to Europe if EU countries described his forces' move as an occupation.

"They are not honest, they just make up words," Erdogan said, singling out Saudi Arabia and Egypt. "We, however, take action and that is the difference between us," he told officials from his ruling AK Party in Ankara.

NATO-ally Turkey has said it intends to create a "safe zone" for the return of millions of refugees to Syria. But world powers fear Turkey's action could intensify the conflict, and runs the risk of Islamic State prisoners escaping from camps amid the chaos.

Turkey's operation began days after a pullback by US forces from the border, and senior members of US President Donald Trump's own Republican Party condemned him for making way for the incursion and abandoning Syrian Kurds, loyal allies of Washington in the fight against the Islamic State in Syria.

"Our heroic commandos taking part in Operation Peace Spring are continuing to advance east of the Euphrates [­river]," the Turkish Defense Ministry wrote on Twitter. 

"The designated targets were seized," it said in a later statement.

Syria's Kurds said Thursday that Turkish bombardment had hit a prison they use to house captured Islamic State group fighters, despite Ankara's pledge to do nothing to undermine the campaign against the jihadists.

"The Turkish regime... targeted a section of the Jerkin prison," in the Kurdish-majority city of Qamishli in the northeast, the region's autonomous Kurdish administration said.

"The prison houses some of the most dangerous criminals from more than 60 countries, who committed all kinds of crimes when they were members of the IS group," it added.