JAKARTA (Reuters) - Two Indonesians were kidnapped from fishing vessels in waters off Malaysia’s Sabah state in two separate incidents on Saturday, Indonesia’s foreign minister said, the latest in a string of abductions in the region.

Malaysian domestic media reported earlier on Sunday that the two boat captains were kidnapped around midday by armed men on speedboats.

It was unclear if the armed men were criminals or belonged to militant groups operating in the area.

The Islamist group Abu Sayyaf, based in the southern Philippines, has carried out kidnappings in the region, beheading some hostages and extorting millions of dollars in ransoms.

Indonesian Foreign Minister Retno Marsudi sent messages to her counterparts in Malaysia and the Philippines to convey her concerns and to request their attention to the matter, she told Reuters on Sunday via text message. Marsudi did not provide further details.

The Indonesian consulates in Kota Kinabalu and Tawau, Malaysia, are working with Malaysian authorities, the owners of the vessels and other crew members to gather further information on the incident, Lalu Muhamad Iqbal, Indonesian citizen protection director at the ministry, said in a written statement received by Reuters.

There are around 6,000 Indonesians working on Malaysian fishing vessels in that area, Iqbal said.

“The Indonesian government has also recommended for Indonesian crew members in Sabah to not go out to sea until the safety situation is seen as conducive,” he said in the statement.

The region around Indonesia’s borders with Malaysia and the Philippines, a major sea lane and fishing area, has seen a spate of kidnappings by gunmen and Islamist militants in recent months.

Indonesian authorities earlier this year blocked some coal shipments to the Philippines amid fears piracy in the region could reach levels previously seen in Somalia.

An Indonesian tugboat crew member swam to safety in August after escaping militant captors in the Philippines.