JAKARTA, May 24 (Xinhua) -- The Indonesian transport ministry has issued a warning to airliners alerting them about volcanic ash from the country's most active volcano Merapi in Java island, spokesman of the ministry Bambang Ervan said.

The warning was issued at 03:56 a.m. Jakarta time on Thursday by the AirNav Indonesia, the spokesman said.

"The airliners are advised to be cautious about the volcanic ash," he told Xinhua by phone.

A further evaluation would be undertaken after the issuance of the advice, said Bambang.

Mount Merapi, located at the borders of Central Java province and Yogyakarta province, erupted earlier on Thursday with an ash column spewed as high as 6,000 meters into the sky.

Residents in the affected areas have been advised to use masks, the National Volcanology Agency said.

Mount Merapi, the most active one of Indonesia's 129 active volcanoes, has regularly erupted since 1948.