Eight Ugandan servicemen walked away from their helicopter after it crashed in Kenya en route to war-torn Somalia while two soldiers were confirmed dead in another crash, officials said Tuesday.

Theirs were among three Russian-made Mi-24 combat helicopters that went down Sunday in a remote mountainous region of Kenya. One was found on Monday, with all seven servicemen on board rescued. Uganda has blamed poor weather for the crashes.

"We have rescued eight survivors," said Simon Gitau, a senior warden with the Kenya Wildlife Service, which is involved in the rescue operation. "All of them were in the helicopter that crashed but did not catch fire."

The eight survivors found Tuesday had trekked some five miles (eight kilometres) through dense forests in search of help.

"They are in good condition after walking away from the crash site," Gitau said. "All of them have been airlifted to safety," he said, adding: "We are now using sniffer dogs to help trace more survivors, if any, in the forest."

The aircraft came down in thickly forested mountainous terrain dominated by snowcapped Mount Kenya, Africa's second-highest peak at 5,199 metres (17,057 feet). Wild animals including elephants, leopards and rhinos prowl the forests, about 110 kilometres (70 miles) north of the capital Nairobi.

Kenyan President Mwai Kibaki offered his condolences to Uganda and promised "thorough investigations" into the crashes, he said in a statement Tuesday, although Kampala said initial reports said the craft crashed in poor weather.

"Preliminary information ... suggests that it was weather to blame," Jeje Odongo, Uganda's state minister for defence, told reporters.

Wreckage of the two helicopters were found early Tuesday morning, with two dead bodies sighted in one that was still on fire.

"The helicopter is still burning, but we do not know if those were the only two soldiers inside or if there are others. We are yet to confirm that," Gitau added.

It had earlier been reported that both aircraft had been burnt.

Uganda said that at least 14 servicemen were thought to have been aboard the two ill-fated helicopters. If that estimate is accurate, then four remain unaccounted for.

The helicopters were flying to Somalia to support African Union troops battling Shebab insurgents linked to Al-Qaeda who have vowed to topple the country's Western-backed government.

An Mi-17 transport helicopter that had taken off from Uganda on Sunday as part of the same mission landed without problems in the eastern Kenyan town of Garissa near the Somali border for a scheduled refueling stop.

Uganda provides around a third of the nearly 17,000-strong AU force in Somalia, and Kampala had said last week that it would send its first combat and transport helicopters to the Horn of Africa nation.

The aircraft are seen as key to extending gains made against the hardline Shebab insurgents, who have fled a string of stronghold towns in recent months, stretching AU military resources over a far wider zone.

The United Nations warned Tuesday of an "imminent" attack on the southern Somali port of Kismayo, the largest remaining stronghold of the Shebab.

The crashed helicopters would have greatly aided forces ahead of any assault on Kismayo by AU forces.

Kenya invaded southern Somalia last year to attack Shebab bases across its eastern border before later joining the AU force.

It has deployed its own air force -- including attack helicopters and fighter jets -- to bombard Shebab positions.

Somalia's weak and corruption-ridden transitional government -- in power for eight years -- is due to be replaced later this month through a UN-backed process in which elders will select new leaders.