Two Indian Coast Guard sailors on board a Sri Lankan fishing boat being towed to Chennai are missing from the last two days, officials said on Friday.
Officials said the boat might have strayed into Sri Lankan waters and there was delay in rescuing the sailors as contact could not be established with fishermen on board.
The Coast Guard is also in touch with Sri Lankan authorities to get the sailors released.
On Wednesday night, a Coast Guard patrol ship spotted Sri Lankan fishermen on seven boats fishing in Indian waters, intercepted them and deployed two sailors on each of the vessels before towing them towards Chennai.
After some time, the seventh boat with five fishermen and two sailors was found missing, amid suspicision that they might have been overpowered by the former.
Sri Lankan fishermen often stray into Indian waters to net prize catch like tuna and end up in Coast Guard and police custody.
Coast Guard officials said the other six boats are in their custody.