Turkey summoned the Swiss ambassador on Monday to complain about a decision by Swiss officials to launch checks to see whether Turkey's EU affairs minister had breached the law by denying Ottoman Turks had committed genocide against Armenians nearly 100 years ago, a Turkish Foreign Ministry official said.

This is not acceptable. The envoy has been summoned for an explanation, the official told Reuters.

According to media reports, Turkey's EU Affairs Minister Egemen Bagis said late last month at the World Economic Forum in Davos and also at a concert in Zurich that the killing of Armenians by Ottoman Turks was not genocide.

Swiss anti racism laws make it illegal to deny a genocide.

Last month, France approved similar legislation, prompting an angry response from Turkey. Turkish Prime Minister Tayyip Erdogan termed the legislation discriminatory and racist.

More than 130 lawmakers who had voted against the bill have appealed to France's highest court, the Constitutional Council, to overturn the law, arguing that the events in 1915-17 were still the subject of historical contention, and the legislation ultimately infringed the right to free speech.

The court has a month to decide.

Armenia, backed by many historians and parliaments, says about 1.5 million Christian Armenians were killed in what is now eastern Turkey during World War One in a deliberate policy of genocide ordered by the Ottoman government.

The Ottoman empire was dissolved at the end of the war, but successive Turkish governments and the vast majority of Turks believe the charge of genocide is a insult to their nation. Ankara argues there was heavy loss of life on both sides during fighting in the area.

An attorney for the Zurich state prosecutor's office said Swiss officials had started an initial probe into Bagis's remarks after receiving a complaint from the Switzerland-Armenia group.

It's all in the initial stages, Christine Braunschweig, an attorney for the Zurich state prosecutor's office, said on Monday. We're don't yet know how, what or when any remarks were made.

Braunschweig said the group Switzerland-Armenia had notified Swiss authorities about the minister's remarks. As a minister, Bagis may enjoy immunity from prosecution.

Swiss authorities have taken legal action against several people who have denied the Armenian genocide. The most prominent case is the conviction of Turkish politician Dogu Perincek, who was fined 3,000 Swiss francs in 2007.

(Reporting by Tulay Karadeniz and Catherine Bosley; Editing by Alison Williams)