Hundreds of flights of German flag carrier Lufthansa were cancelled after about 4,000 pilots went on a strike on Monday.

Lufthansa said in a statement: 'We hereby confirm that the strike, which was initiated by the Vereinigung Cockpit trade union, began at midnight' (2300 GMT on Sunday). The strike is due to run for four days. Monday was also the final day of a cabin crew strike ballot at Lufthansa's rival British Airways over similar action.

The airline said despite the strike, it was maintaining many domestic flights and short-haul routes across Europe, though many of its long-haul flights to the US, including New York and Denver, were cancelled.

'Usually we have 1,800 flights a day,' the airline said. 'For today, we foresee about 1,000 flights planned, but there may be more flights that could be cancelled.'

Lufthansa's pilots voted for the strike on concerns that the company could try to cut staff costs by shifting jobs to foreign subsidiaries such as Austrian Airlines or Lufthansa Italia, where wages are lower.

Over the weekend, the pilots' union offered new negotiations, but Lufthansa said it would not resume talks unless the union dropped demands for what it saw as undue influence on managerial decisions.

Lufthansa board member Stefan Lauer told the Frankfurter Allgemeine Sonntagszeitung paper on Sunday that the company was prepared to guarantee all pilots' jobs until the end of 2012. It could extend that guarantee until 2013 or 2014 if pilots were willing to forego pay raises for more than 12 months, he said.

Lufthansa has said the strike will cost it about 100 million euros ($135 million) in cash, in addition to lost ticket sales and possible damage to its reputation.