ISTANBUL - Tensions ran high between the Turkish government and trade unions ahead of May Day Thursday as demonstrations were banned at an iconic square in Istanbul, the scene of bloodshed three decades ago.

Istanbul Governor Muammer Guler said the authorities had intelligence that "some marginal and illegal" groups would attempt to provoke unrest on May Day by attacking the security forces with stones and petrol bombs, and even using firearms.

The police, he warned, would use force to disperse any gathering at Taksim square, a traditional venue for celebrations in the heart of Istanbul.

Many trade unions, among them the largest Turk-Is and the leftist DISK, insist on gathering at Taksim to commemorate the killing of 34 people there on May Day in 1977 amid political unrest.

Prime Minister Recep Tayyip Erdogan held talks with labour leaders Tuesday in a bid to persuade them to agree only to a small wreath-laying ceremony at the site of the bloodshed.

"The trade unions naturally have the right to mark this day, but we are a state of law and they must respect the law," Erdogan said.

Relations between the government and trade unions are already strained over an unpopular social security reform the ruling Justice and Development Party passed through parliament this month under pressure from the International Monetary Fund.

The 1977 bloodshed took place at a time of severe political tensions and street violence between leftist and rightist militants in Turkey, which eventually led to a military coup in 1980.

The deaths occurred when unknown gunmen, believed to be far-right militants aided by members of the secret service, fired on a peaceful crowd, triggering mass panic.

Since the 1980 coup, May Day has seized to be a public holiday in Turkey and Erdogan's government last week refused to re-instate it as such, despite strong pressure from trade unions.

Last year, some 900 people were detained on May Day in Istanbul as the police fought pitched battles with left-wing activists who insisted on gathering at Taksim square.

Outlawed extremist groups and separatist Kurdish militants regularly take May Day demonstrations as an opportunity to attack the police.

At least 20,000 policemen are expected to be on duty in Istanbul Thursday, according to media reports.

The authorities also worry that a crowded gathering in the heart of Istanbul could paralyse the already chaotic traffic in the city, Turkey's industrial and financial capital with a population of some 13 million.

Governor Guler has suggested four other venues for the trade unions to hold their demonstrations, two each on the city's European and Asian sides.

Trade union leaders, however, remain reluctant on giving up Taksim.

"May 1 is a day of solidarity and brotherhood for workers. Why shall we be deprived of it?" DISK chairman Suleyman Celebi said.

Protests at the new social security law, which brought tougher retirement conditions described by trade unions as "retirement in the grave," are expected to be one of the main features of Thursday's demonstrations.

ba-su/rlp

04/29/2008 12:09 GMT