COLOMBO (AFP) - Sri Lanka's military has banned foreigners from travelling to the island's former war zone during a visit there by President Mahinda Rajapakse, officials and diplomatic sources said on Sunday.

Foreigners were turned back at Omanthai, the army-controlled entry point to the Northern Province which the president is visiting, the diplomatic sources said.

Military officials said the travel ban had been in place since Friday and was in the "national interest". The police said they had no role in turning back foreigners at Omanthai.

Among those affected were people of Sri Lankan origin on their way to attend weddings, funerals and religious rituals in Jaffna, the cultural capital of ethnic Tamils, the privately run Sunday Times newspaper reported.

Diplomatic sources said foreign experts working on development projects in the former war zone had also been turned back, despite having permission to work there.

Mr Rajapakse is visiting the Northern Province for the reopening Monday of a railway line to the provincial capital Jaffna.

He will also chair a meeting to review construction work in the battle-scarred area, where troops crushed Tamil separatists in May 2009 and declared an end to 37 years of ethnic bloodshed.

Sri Lanka has repeatedly warned that minority Tamil groups abroad may try to revive the defeated Tamil Tigers, who fought for an independent homeland for the island's main ethnic minority.

However, since the end of fighting in 2009 no attacks have been blamed on the Tamil Tiger rebels, who at the height of their power controlled a third of the country's territory.

The United Nations has estimated that up to 100,000 people may have been killed in the separatist conflict between 1972 and 2009.