The killing of two Indian fishermen off the Kerala coast in firing allegedly by two Italian marines on board an oil tanker is an 'unpardonable crime' and the guilty would be punished, Shipping Minister G K Vasan said here today.

"As I have already said it is condemnable. They (Kerala police) are looking into it as a suspicious incident. Our waterfront is not infested by pirates.So it is an unpardonable crime to shoot innocent fishermen thinking they are pirates.

There is no second opinion on whether to punish them for the act," he told reporters on the sidelines of a function here.

Asked if the marines would be tried under Indian law, he said, "One thing I am very clear. Punishment should be given to the guilty. We have lost two precious lives of fishermen, which cannot be pardoned, which cannot be taken for granted.

Assuring that steps would be taken to prevent recurrence of such attacks, he said "The Mercantile Marine Department under the Shipping Ministry, along with Defence, Law and External Affairs ministries are investigating the issue and the guilty will be punished...Centre will give full protection to them."

The two fishermen, Ajesh Binki (25) and Jalastein (45) were killed on February 15 off Kollam coast near Kerala when armed guards of 'Enrica Lexie' fired at their boat.

Preliminary assessment of marine authorities is that the guards might have fired at the boat, mistaking it for a pirate vessel.