FILE - Sri Lankan air force paratroopers get ready for an exercise at an air force base in Ratmalana, a suburb of Colombo, Sri Lanka.
FILE - Sri Lankan air force paratroopers get ready for an exercise at an air force base in Ratmalana, a suburb of Colombo, Sri Lanka.

COLOMBO - Sri Lanka has suspended flight training near its biggest air force base due to security concerns after suspected Islamist militants killed more than 250 people last month, according to a government directive seen by Reuters on Thursday.

Sri Lanka has been on high alert since multiple suicide bombings on Easter Sunday targeted churches and hotels. Islamic State claimed responsibility for the attack.

Flight training has been suspended at Ratmalana, a suburb in the capital Colombo, the country's Civil Aviation Authority said in a letter to flying schools and aircraft operators.

Training will only be allowed from the Katukurunda domestic airport, around 35 km (22 miles) south of Colombo, and flights can only fly to the south of that base, according to the letter.

A copy of the letter, dated April 30th, was seen by Reuters. The new rules are effective immediately.

Sri Lanka suspended training at Ratmalana during the peak of the civil war with Tamil separatists fearing air attacks.

The letter cites new rules "in view of the prevailing security threat to the national defense, lives of public and properties."

The new guidelines also suspend recreational and leisure flights such as sky diving.

No training flights have been operated for two weeks since the rules came into place due to difficulties in moving training operations to Katukurunda, according to a source familiar with the matter.