Islamabad - Rescue teams supported by Pakistan's army launched an operation Saturday to rescue two Italian climbers stranded four days ago some 7,000 metres up a Himalayan peak.

Simon Kehrer and Walter Nones were climbing a new route on Nanga Parbat, altitude 8,126 metres, when rain and storms opened up many crevasses, blocking their way back to the base camp. Their colleague, world-renowned Italian climber Karl Unterkircher, fell into a ravine and died.

"A Pakistan Army's helicopter, carrying an Italian rescue team, overflew the two survivor climbers around 7 am local time (0100 GMT), and they waived at the rescuers," said Rashid Ahmad, spokesman for Hushe Trecks and Tours, the tour operator that arranged the Nanga Parbat expedition.

The Italian embassy in Islamabad confirmed that the rescue operation was underway.

"They are alive and well. They are in a tent," said embassy spokesman Ogdo Sargio.

The first drop of supplies to the alpinists was "useless," as the walkie-talkie set and the food fell on a spot that the climbers could not reach, he said.

"It is a difficult area. The helicopter flew past the spot quite fast, and now the rescue team is trying to convey a message to them that they should come down to a plain area, where the helicopter could drop food and equipments for them," said Sargio.

The team, comprising Silvio Mondinelli and Maurizio Gallo, who arrived Friday from Milan, would make another attempt to drop food later Saturday.

Bad weather hampered the rescue operation on Friday, but the conditions were favourable Saturday. (dpa)