Leaders of the international maritime trade unions wrote a letter to the United Nations urging the organization to take action against the increasing attacks of pirates on civilian vessels, Nikolai Sukhanov, the chairman of the Russian Professional Union of Sailors, said on Monday.

“Cases of sailors’ abductions by pirates continue. Representatives of the fisheries committees with the International Transport Federation voice concern that sailors are still objected to humiliation and injuries as they are abducted by pirates,” he said.

“Unfortunately, ransom is still the only guarantee for a safe liberation of sailors, but trade union leaders note that some countries want to prohibit paying ransoms,” Sukhanov added.

He said that if the payment of ransoms for the release of captured sailors is ruled as illegal, it would lead to unpredictable consequences and jeopardize the lives of sailors in case of pirate attacks.

Somali pirates pose a significant threat in the Gulf of Aden and the Arabian Sea, where they have robbed and seized numerous vessels. Some shipping firms have started hiring armed security to protect their ships from pirates. Since 2010, there have been regular attacks on vessels in the western Indian Ocean approaching the coast of India.