The French Senate has approved a controversial bill that makes it a criminal offence to deny that genocide was committed by Ottoman Turks against Armenians during World War I. The Senate approved the bill by 127 votes to 86.

The measure will now be sent to President Sarkozy for final approval.

The bill's passage in the lower house caused major tensions with Turkey. Ankara froze ties with France after the vote last month and promised further measures if the Senate backed the proposal.

The BBC's correspondent in Istanbul, Jonathan Head, says stronger Turkish measures could include the withdrawal of ambassadors and creating more barriers to French businesses in Turkey.

In the first reaction from Ankara, Justice Minister Sadullah Ergin condemned the bill. He told the CNN-Turk television channel:

The decision made by the Senate is a great injustice and shows total lack of respect for Turkey.

The Turkish embassy in Paris warned that if President Sarkozy approved the bill, the damage done to relations between the two countries would be permanent.

The Turkish prime minister has said a bill passed by the French parliament on the mass killing of Armenians under Ottoman rule is racist.

Recep Tayyip Erdogan told the Turkish parliament in Ankara that the bill murdered freedom of thought.

This is a racist and discriminatory approach and if you cannot see this, then you are deaf to the footsteps of fascism in Europe.

Turkey, he added, hoped for the success of a French appeal against the bill to the constitutional commission.

We will wait and see the developments and decide on our reply to them, he said.

Turkey, which rejects the term genocide, has said the number of deaths was much smaller.

Swiss prosecutors have launched an initial investigation to see whether Turkey's EU minister breached the law by denying that the mass killings of Armenians a century ago were genocide.

According to media reports, during a recent visit to Switzerland Egemen Bagis denied that there had been an Armenian genocide, adding Let them come and arrest me.

Under Swiss law it is a crime to deny that the killings of up to 1.5 million Armenians during World War One constituted an act of genocide.

A Turkish Foreign Ministry official, speaking on condition of anonymity, later said Turkey had summoned the Swiss ambassador to Ankara to tell him that the probe was "unacceptable."

French President Nicolas Sarkozy has ordered his government to draft a new law punishing denial of the Armenian genocide after a top court struck down a previous bill.

The Constitutional Council earlier ruled the law backed by Sarkozy infringed on freedom of expression. The bill, which covers the mass killing of Armenians by Ottoman Turks during World War I, was passed by both houses of the French parliament.

Turkey welcomed the ruling. But now Sarkozy seems set on re-opening Turkish antagonism. Noting the great disappointment and profound sadness of the law's backers, Sarkozy's office wrote in a statement:

The President of the Republic considers that [genocide] denial is intolerable and must therefore be punished. He has asked the government to prepare a new draft taking into account the decision of the Constitutional Council.