PRISTINA, Kosovo — Kosovo police arrested six Turks working with a group of schools owned by a cleric who President Recep Tayyip Erdogan blames for an attempted coup two years ago and handed them over to Turkish authorities Thursday, officials said.

Turkey's state-run Anadolu Agency said Turkish intelligence agency MIT used a private plane to take those arrested back to Turkey. They have been handed over to the judiciary.

Those sent back are said to be from a school network that belongs to Fethullah Gulen, the cleric Erdogan blames for the 2016 failed coup in Turkey. Gulen, who lives in the U.S., denies the claim.

Anadolu Agency said the six were "alleged senior Fetullah Terrorist Organization (FETO) members" and were arrested "following operations against the terror group's branch in the Balkans."

Turkish police said they had found evidence of how they have operated in the Balkans: fundraising, allegedly recruiting terror group members, forging documents, or taking part in the conspiracy to overthrow the Turkish government.

In a statement earlier, Kosovo's Interior Ministry said those arrested had their residence permits revoked, without providing any reason why.

According to Kosovo law, the ministry can revoke residency permits for security, criminal, health, public moral or human rights threats.

Dozens of students of the Gulen-owned schools held a protest in downtown Pristina calling for the release of the six.

Kosovo's Prime Minister Ramush Haradinaj said in a statement that he wasn't informed of the police operation and that he was trying to understand "the constitutional and legal responsibilities of that action and the unclear things about it."

Haradinaj convened an urgent meeting of his Cabinet. He asked the heads of intelligence agencies and police departments, and the interior and justice ministers to report why authorities revoked the permits of the six Turks, and why they were arrested and deported "in urgency and in secrecy."

President Hashim Thaci, too, was "disillusioned how our relevant institutions" failed to protect foreign citizens working in Kosovo, adding that he learned about it after the arrest.

Kosovo's foreign ministry strongly denounced the action, saying that "the arrest and deportation of the Turkish citizens with a regular residence permit ... is ... in direct contradiction to international norms."

"That should not have happened under any circumstances," a statement said. "The Foreign Affairs Ministry opposes such an action and also expresses its deep regret to the family members of the deported."

Turkey has been a main supporter for the new state, Kosovo, which declared independence in 2008.

The Gulistan Education Institutions confirmed the arrests, saying the managers were taken away in "a mysterious way."

Lawyer Urim Vokshi said they were arrested after intelligence agents "identified them as dangerous, without offering any reason or proof."

Nazmi Ulus, a senior manager of the Gulistan network in Kosovo, said they all had legal residence permits.

"These are the effects of the Erdogan regime in Balkan countries or in other Asian and African countries," he told the Associated Press.

The Council for the Defense of Human Rights and Freedoms, or KMDLNJ, a human rights group in Kosovo, urged the government not to interfere in the fight between Erdogan and Gulen.

"The KMDLNj opposes the arrest of the Turkish citizens in Kosovo for political reasons and strongly opposes any effort of their extradition in the current circumstances," it said a statement.