Icelandic whalers have killed the first two fin whales of the season after resuming their controversial commercial hunt earlier this week, whaling officials said Wednesday.

One fin whale was brought to port late Tuesday, and another one killed early Wednesday was expected to be brought in to port on Thursday, Gunnlaugur Gunnlaugsson, the head of the Hvalfjordur whaling station, said.

A third whale was also being hunted on Wednesday.

The whaling ships Hvalur 8 and Hvalur 9 left for the hunt late Sunday. Hvalur is the only company that hunts the giant mammals, the second largest whale species after the blue whale.

The International Fund for Animal Welfare attacked Iceland's resumption of the fin whale hunt as "cruel and unnecessary."

"It is a very sad day ... knowing that this endangered animal has suffered a cruel death, only to be cut up for meat that nobody needs," Robbie Marsland, the British director of IFAW, said in a statement.

"It is time that this dying industry was ended," Marsland said.

This season's quota for fin whales is set at 154 whales, with the possible addition of some 20 percent from last year that were never hunted.

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.

Iceland also hunts minke whales, a smaller species. That hunt began in May, and so far at least 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.