9:49am BST

By Fatos Bytyci

PRISTINA (Reuters) - Police in Kosovo arrested 15 people on Wednesday, including a number of imams, in the second major operation in weeks to stem the flow of young ethnic Albanians joining Islamist fighters in Iraq and Syria, a police source said.

Local media reported that an influential imam of the Grand Mosque in the capital, Pristina, was among those arrested, as was the leader of an Islamic-rooted political party.

Most of Kosovo's 1.8 million people are ethnic Albanian Muslims and lead largely secular lives.

A police source, who spoke on condition of anonymity, told Reuters: "We have arrested 15 people from all over the country. The charges include terrorism, threatening the constitutional order, incitement and religious hate speech."

A police spokesman said "some people" had been arrested in an operation launched in the morning, but declined to elaborate.

The swoop follows the Aug. 11 arrest of 40 people on suspicion of fighting in Iraq and Syria or recruiting insurgents.

Fears of a creeping radicalisation among their Muslim communities are stirring in other Balkan countries - such as Serbia and Bosnia - with dozens of their citizens also known to have joined Islamist fighters in the Middle East.

Intelligence officials in Kosovo believe between 100 and 200 Kosovars are fighting in Iraq and Syria, where Islamic State militants have seized swathes of land, drawing U.S. air strikes. At least 20 are reported to have been killed in the past year.

Landlocked and impoverished, Kosovo won independence from Serbia in 2008, almost a decade after a U.S.-led NATO air war drove out Serbian forces accused of killing and expelling Albanian civilians during a counter-insurgency campaign.