Yangon, Oct 14 (IANS): Myanmar's Mandalay regional police force has confiscated some documents related to a terrorist organisation which are believed to have been left by a foreigner in a domestic scheduled flight, sources said Tuesday.

The documents containing some details about the Islamic State (IS) terrorist group were found by cleaners of the Kanbawza Airline at Thada Oo Airport of Mandalay when the flight stopped over there on its arranged schedule from Yangon to Heho via Nyaung Oo and Mandalay, reported Xinhua citing the sources who quoted the police as saying.

The passenger had got out at Nyaung Oo airport before the documents were discovered, Xinhua reported citing the sources.

Investigations are under way in the case.

Myanmar authorities have tightened security in Yangon region, especially religious buildings, ever since Al Qaeda leader Ayman al Zawahiri announced a new focus on Myanmar, Bangladesh and India in September.

Earlier September, a video featuring Zawahiri describing the launch of a new branch in the Indian subcontinent with the aim of expanding jihad to the region was released.

The Burmese Muslim Association (BMA) refused to accept the Al Qaeda statement, urging people to live together in harmony regardless of racial and religious differences.

Precautionary measures have been reportedly taken by armed forces to beef up checkpoints and monitor infiltration of terrorists.