The official, Salih Muslim, is the foreign affairs spokesman for the political coalition that governs the Kurdish regions of northern Syria, the Movement for a Democratic Society. He was detained after an Interpol “red notice” was issued by the Turkish government, which describes him as a terrorist, the agency said.
The Czech police issued a statement confirming the arrest of a 67-year-old man on a Turkish extradition request. Mr. Muslim’s aides confirmed that the statement referred to him.
An official with the Kurdistan National Congress in Vienna said that Mr. Muslim had been arrested at his hotel in Prague, the Czech capital, where he was speaking against Turkey’s invasion of the Kurdish enclave of Afrin, in northwestern Syria.
Though an Interpol red notice is a request from a country to detain someone for extradition, it is not itself a criminal charge.
Mr. Muslim was formerly the co-president of the Democratic Union Party (known as the P.Y.D.), the political arm of the Kurdish Peoples Protection Units, or Y.P.G., in Syria.
Turkey claims the P.Y.D. and Y.P.G. are part of the Turkish-based Kurdistan Workers’ Party, or P.K.K., which was designated as a terrorist organization by the European Union and the United States, although the Syrian organizations were not.
The Y.P.G. is the dominant group in the Syrian Democratic Forces, which are partners with the American-led international coalition fighting the Islamic State in Syria. And American officials have had high praise for the organization’s military and political wings, despite Turkish criticism.
In a recent phone interview from Brussels, where he is based, Mr. Muslim rejected Turkish claims that the Kurds’ Syrian organizations in Rojava, or northern Syria, were fronts for the P.K.K.
“We belong in Rojava; we have organized our people in Rojava.” he said. “But that doesn’t mean we are P.K.K. Also, we decide for ourselves.” He added, “The Turks are just using the P.K.K. as an excuse to make something against us. To the Turks, the best Kurd is a dead Kurd.”
Last month, Turkey began an offensive in Afrin and threatened to carry its fight against Syrian Kurds into Manbij and areas farther east where American troops are stationed, which the United States military vowed to resist.
Mr. Muslim is now with a political coalition representing the Rojava region in Syria, but it is closely aligned with the P.Y.D. and its military wing.
President Recep Tayyip Erdogan of Turkey, addressing his party supporters in the southeastern province of Sanliurfa, said, “Now the head of P.Y.D. is caught,” according to Anadolu. “Our wish is, God willing, for the Czech Republic to hand over him to Turkey, and justice prevails.”
A statement issued by Mr. Muslim’s organization, the Movement for a Democratic Society, denounced the arrest. “The Turkish state has no right to prosecute or arrest any person who is not one of her citizens,” it said. “Salih Muslim is a Syrian citizen.”
Many Interpol red notice detentions are dismissed by the courts in the countries where they take place, without the extraditions. Europe has not designated the Syrian Kurdish organizations as terrorist groups, and it has previously rejected such extradition requests by Turkey.