Colombo: Sri Lanka’s defence ministry on Wednesday announced new curbs on foreigners, including journalists, visiting the island’s former war zone and said the action was to protect “national security".

Foreign passport-holders will require approval from the defence ministry if they want to travel to the battle-scarred northern province, military spokesman Brigadier Ruwan Wanigasooriya said.

“We have information some foreigners are trying to cause discord among ethnic communities," Wanigasooriya told reporters in Colombo.

“When there’s a tremendous threat like that to our national security, we can’t just wait. We have to take action."

The new move came after foreign nationals were turned away from the northern province last Friday, ahead of a visit there by President Mahinda Rajapakse.

The president on Monday relaunched a rail link to Jaffna, the capital of the northern province, to restore train services after nearly 25 years.

The new controls come amid a UN-mandated international investigation into Sri Lanka’s war record.

Colombo has already accused several Colombo-based diplomatic missions as well as foreigners of trying to collect testimony from survivors to support allegations of rights abuses by security forces during the civil war which ended in 2009.

Sri Lanka has refused to cooperate with the probe ordered by the UN Human Rights Council and says it will not allow foreign investigators to probe allegations that up to 40,000 ethnic Tamil civilians were killed by troops in the final months of fighting.

Sri Lanka denies any civilian was killed by its security forces, but following intense international pressure agreed to probe the allegations through a domestic commission of inquiry.

Foreign nationals, including aid workers were barred from the north from Friday just before Rajapakse visited the area.

Wanigasooriya said travel restrictions on foreign journalists will also be brought back three years after Colombo relaxed them.

He said journalists holding foreign passports will have to apply to the defence ministry for permission to travel to the north.

The new restrictions on all foreigners will affect a large number of Sri Lanka’s ethnic minority Tamils who have obtained foreign passports after having fled the fighting and living abroad as refugees for long periods.

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