Blizzards hampered a search and rescue operation on Friday for a Norwegian military transport plane with five crew feared to have crashed in a Swedish Arctic mountain range, rescuers said.

"It's terrible weather. And it's very difficult to find an aircraft in the hilly terrain," a spokesman for Sweden's air rescue services, Peter Lindquist, told AFP.

The harsh weather conditions also complicated search and rescue efforts on Thursday night to locate the  plane in the mountains of north-western Sweden.

Strong winds and heavy cloud cover forced helicopters to break off their overnight search for the plane, which was carrying five Norwegian crew members when it lost radio and radar contact around 2.40pm on Thursday afternoon.

However, helicopters were back in the air by Friday morning, concentrating their search in three areas around Mount Kebnekaise, Sweden's tallest peak.

"These are the areas that are most likely [for the plane to be located] based on the last radar signal we have and a spot which a heat sensing camera from a Norwegian surveillance aircraft picked up last night," rescue operations leader Jonas Sundin of the Swedish sea and air rescue services told the TT news agency.

In addition to the difficult weather conditions, avalanche concerns complicated ground-based rescue efforts.

"There are a few ground patrols out and driving around on snowmobiles, but there is a great risk for avalanches. We have a lot of manpower at the ready, but we're limited by the avalanche danger," said rescue operations leader Bengt-Olov Hammarlöf to TT.

"It's only the most experienced [rescuers] who can go into these areas when it's dark."

So far, no emergency signals from the missing plane have been detected.

"For some reason, it hasn't been set off. Either the crash was so violent or so terrible that it was knocked out of operations by the impact, but there is also an emergency signal transmitter in the life vests but those must be switched on by hand and for that, you have to be conscious," said Hammarlöf.

The aircraft went missing when it was on its way from Evenes in northern Norway to Kiruna in the far north of Sweden.

At the time, the Hercules was was participating in the Cold Response military training exercise taking place over northern Norway which was scheduled to run from March 12th to March 21st and included 16,000 soldiers from 15 countries.

"There was a crew of four on board as well as an extra officer. Their mission was to fly from Evenes to Kiruna to pick up materiel and personnel and fly back to Norway," Harald Sunde, head of the Norwegian Armed Forces told Norwegian news agency NTB.

He added that the officers on board the Hercules aircraft were among the "most experienced" in the Norwegian military and that there were no clues regarding what may have happened.

"We have nothing that points us in any particular direction. This is a very robust and new aircraft, one of the best there is. It's been hard to have bad luck with this type of aircraft," said Sunde.

The missing aircraft is a C-130 J "Super" Hercules transport plane manufactured by Lockheed Martin in the United States.

The plane is one of four C-130 Js ordered by the Norwegian air force in 2007, the first of which was delivered in November 2008.

Map: Rescuers believe the plane crashed at Drakryggen, near Mount Kebnekaise, Sweden's highest peak.

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