Iceland has resumed its disputed commercial fin whale hunt, with two vessels en route to catch this season's quota of at least 154 whales, Icelandic media reported on Monday.

An international website that tracks vessels showed two Icelandic whaling ships, Hvalur 8 and Hvalur 9, well west of Iceland on their way to whaling areas, while national media said the two ships left port late Sunday.

Hvalur, the only company that hunts the giant mammals, was unavailable for comment on Monday, which was a public holiday in Iceland.

Hvalur killed 148 fin whales in 2010, but none in 2011 and 2012 due to the disintegration of its only market in quake- and tsunami-hit Japan.

In May, the company said this year's quota had been set at 154 fin whales, with the possible addition of some 20 percent from last year that were never hunted.

Fin whales are the second largest whale species after the blue whale.

Iceland also hunts minke whales, a smaller species. That hunt began in May, and so far seven minke whales have been harpooned, whaling officials said.

The International Whaling Commission imposed a global moratorium on whaling in 1986 amid alarm at the declining stock of the marine mammals.

Iceland, which resumed commercial whaling in 2006, and Norway are the only two countries still openly practising commercial whaling in defiance of the moratorium.

Japan also hunts whales but insists this is only for scientific purposes even if most of the meat ends up on the market for consumption.

In 2011, the United States threatened Iceland with economic sanctions over its commercial whaling, accusing the country of undermining international efforts to preserve the ocean giants.

But President Barack Obama stopped short of sanctions, instead urging Reykjavik to halt the practice.