NICOSIA -- Cyprus's Army and Air Force commanders were killed early Wednesday when their helicopter crashed near Paphos in the southwest of the island, apparently while trying to make an emergency landing, authorities said.

National Guard Chief Lieutenant General Evangelos Florakis, 59, and air force head wing commander Stelios Demenagas, 50, who were both seconded from the Greek armed forces, died with three other officers while on their way to observe a military exercise in the area.

Cyprus President Glafcos Clerides ruled out sabotage after visiting the crash site at a dry riverbed near the Paphos village of Kouklia, AFP reported.

"It appears the pilot tried to land the helicopter in rough terrain, it was dark and he landed on a steep incline, causing the helicopter to roll over," Clerides told reporters in Nicosia.

He said the pilot had contacted the control tower some 10 minutes before the crash and did not indicate any problem.

Clerides said that Greek experts would arrive later Wednesday to try to ascertain what happened.

He called the death of the popular Florakis "a great loss for Cyprus".

Also killed were Florakis' aide de camp, naval commander Nicholas Georgiou, 29, and helicopter pilots Paris Athanassiades, 31, and Michalis Shakallis, 24, all Greek Cypriots.

Military authorities said DNA tests would have to be carried out to identify the charred corpses.

Three days of state mourning were announced following the worse incident of its kind to hit the National Guard since its creation in 1964.

Wednesday's cabinet session was also canceled, as were parliamentary committee meetings.

"Today is a day of great sorrow, grief, sadness and reflection for the Cypriot people ... our thoughts are with the National Guard members who were lost," said government spokesman Michalis Papapetrou.

Flags on all state buildings and army installations will be flying at half-mast throughout the mourning period.

The Bell 206 helicopter, which had taken off from the Lakatamia Air Base near Nicosia, came down in hilly country some four kilometers (2.5 miles) short of its destination of Paphos' Andreas Papandreou Air Base.

One eyewitness told local television it seemed to be burning before it hit the ground. Wreckage was scattered over a wide area.

Florakis, whose wife comes from Paphos, took over the National Guard in May 2000. Known as a straight talking "People's Man", he leaves two daughters.

It was the first accident for the National Guard's air wing since it was created 18 years ago. The helicopter itself had been in service for less than 10 years.

"This is the price the people of a country must pay when it continues its fight for freedom," said a tearful and shaken Defense Minister Socrates Hasikos.

The National Guard has some 12,000 serving soldiers, mainly Greek Cypriot conscripts, but including senior officers seconded from Greece under a defense agreement.

The island has been divided since 1974 when Turkey seized its northern third in response to an Athens-engineered coup staged by elements in the National Guard and aimed at uniting the island with Greece.

Turkey maintains more than 35,000 troops in the north in the breakaway Turkish-Cypriot state.