COLOMBO, Sri Lanka (AP) — Sri Lanka’s diplomats are talking with Somali authorities trying to ascertain the whereabouts of a fishing vessel and its six crewmembers suspected of being abducted by Somali pirates two days ago, officials said Monday.

The apparent abduction came two weeks after Sri Lanka said it would join a U.S.-led operation to protect merchant vessels sailing in the Red Sea against attacks by Yemen-based Houthi rebels. Other suspected hijackings in waters off Somalia have raised concern that Somali pirates have resumed activity, a decade after they caused chaos in international shipping.

The hijacking of the Sri Lankan vessel occurred in international waters about 840 nautical miles (1,555 kilometers) east of Somalia, 1,100 nautical miles (2,040 kilometers) from Sri Lanka and north of Seychelles, according to Sri Lankan navy spokesman Capt. Gayan Wickramasuriya.

“So far, we have no communication with them or no details on the whereabout of them,” he said.

The Sri Lankan foreign ministry said it was working to obtain the release of the fishermen. “Sri Lanka ambassadors in the African region have already established contacts with Somalian authorities to get the fishermen and trawler released as soon as possible,” ministry spokesman Niluka Kadurugamuwa said.

On Saturday, an armed group arrived in an area where about 30 Sri Lankan vessels were fishing.

Two to three armed men who had arrived in a 23-meter (75-foot) vessel boarded the fishing trawler, fired shots apparently to warn away the other fishing boats and took away the fishing trawler and the fishermen, said Susantha Kahawatta, a top official in the Fisheries Department, adding that all the details of the abduction were provided by fishermen in the other trawlers. The other fishermen identified the attackers as Somali.

Sri Lanka’s navy said two weeks ago it would provide a ship to protect merchant ship traffic, but the date hasn’t been set and the area Sri Lanka will patrol isn’t finalized.