Families of the eight Sri Lankan crew members held captive by Somali pirates on an oil tanker have pleaded for the men to be released unharmed, while the pirates demanded a ransom.
The hijacking on Monday was the first such seizure of a large commercial vessel off Somalia since 2012. It came as a surprise to the global shipping industry as international patrols had suppressed pirate hijackings for several years.
The European Union anti-piracy operation in the region announced late on Tuesday that the armed men were holding the crew captive and demanding a ransom for the ship's release.
Namali Makalandawa, the sister of the oil tanker's chief officer Premnath Ruwan Sampath, said families had tried to contact the shipping company's office in Dubai but their calls were not answered.
"Some fear is developing in our hearts. We fear for the lives of our loved ones," Ms Makalandawa said after meeting with Sri Lankan foreign ministry officials. She said officials and families were meeting with the shipping agent on Thursday.
Families have no way of communicating with the captive crew, Ms Makalandawa said.
"Please release them. I appeal to you because these crew members include fathers, sons and husbands. The have gone to sea to earn money to sustain their families," she said.
The EU statement said the naval operation on Tuesday afternoon finally made contact with the ship's master, who confirmed that armed men were aboard the Comoros-flagged tanker Aris 13.
A Somali pirate who said he was in touch with the armed men aboard the tanker said they have locked most of the crew in one room and cut off communication lines.
"Their main concern now is a possible rescue attempt, so that's why all communications were cut off in the afternoon," Bile Hussein said.
He said the amount of ransom to demand had not yet been decided.
Somali pirates usually hijack ships and crew for ransom.
"They are human. Even the pirates are human. We can talk over this peacefully," Ms Makalandawa said.
The ship had been carrying fuel from Djibouti to Somalia's capital, Mogadishu, when it was approached by men in two skiffs.
A UN shipping database shows the Aris 13 is owned by Armi Shipping SA, whose address is listed in care of Aurora Ship Management FZE, a company based in the United Arab Emirates.