An ethnic Armenian separatist officer in Nagorny Karabakh and an Azerbaijani soldier died in the latest raid along the disputed region's volatile frontline, the rebel defense ministry said Saturday.

Several other Azerbaijani soldiers were captured in the fighting, breakaway Armenian forces said, although Baku has made no comment on the claims.

Azerbaijani troops have shot dead a soldier from the separatist Nagorny Karabakh forces in the latest outbreak of violence along the disputed region's volatile frontline, the rebel defense ministry said on Wednesday.  

"Private Armen Avetisian, 19, was shot dead by Azerbaijani troops on June 24 at the southern sector of the line of separation between Karabakh and Azerbaijani armed forces," the self-proclaimed state's defence ministry said in a statement.

Azerbaijani forces killed an Armenian soldier in a fresh border shoot-out between the arch-foes locked in a smoldering conflict over the disputed Nagorny Karabakh region, the defense ministry in Yerevan said Friday.

"Private Grisha Khachatrian, 20, died Thursday of mortal wounds" when Azerbaijani troops opened fire on the south-western sector of the Armenia-Azerbaijan border, the ministry said in a statement.

Two Armenian troops died on Thursday in a fresh clash with Azerbaijani forces on the volatile border between the two countries, Armenia's defense ministry said.

"Sergeant Andranik Egoyan, 26, and private Boris Gasparyan, 22, were mortally wounded by the Azerbaijani forces on the south-western sector of the Armenia-Azerbaijan border," the ministry said in a statement.

Swiss President Didier Burkhalter on Wednesday called on arch-foes Azerbaijan and Armenia to revitalize stalled negotiations on resolving their decades-long conflict over the disputed Nagorny Karabakh region.

"The status quo is not really an option. We have to move to peace step by step," Burkhalter -- who is also chairman of the Organization for Security and Cooperation in Europe (OSCE) -- told a news conference in Yerevan.

At least three troops died in overnight clashes between Azerbaijani troops and separatist forces of the Armenian-backed breakaway Nagorny Karabakh region, officials in Baku and Karabakh said Wednesday.

The defense ministry in Baku said "a captain and a warrant officer of the Azerbaijani armed forces were killed" in clashes on the Karabakh frontline, while a private was injured.

Armenia on Tuesday invited Turkey's leader to events next year marking the 100th anniversary of World War I-era massacres that Armenians say amounted to genocide, despite Ankara's fierce rejection of the term.

Relations between the two countries have long been soured by disputes over the massacres, in which Armenians say up to 1.5 million people were killed in what is now Turkey as the Ottoman Empire was falling apart.

Azerbaijani troops killed an ethnic Armenian soldier from the disputed Nagorny Karabakh region's forces in a fresh clash along the volatile frontline, the Armenian-backed region's defense ministry said on Wednesday. 

The soldier, "20-year-old Artur Oganjanian, died after he was mortally wounded on Tuesday by Azerbaijani troops at the southern sector of the line of separation of Azerbaijani and Karabakh forces," the ministry said in a statement. 

French President Francois Hollande starts a three-day visit to the South Caucasus on Sunday as he seeks to bolster European ties on Russia's southern doorstep amid the crisis in Ukraine.

Hollande was due to arrive in the Azerbaijani capital Baku around 6:00 pm (1300 GMT) Sunday, on the same day separatists in eastern Ukraine held referendums on breaking away from the country.

Armenian President Serzh Sarkisian on Thursday accused Turkey of an "utter denial" in failing to recognize World War I mass killings of Armenians in the Ottoman Empire as genocide, apparently brushing off Ankara's first ever offer of condolences for the tragedy.

In an unprecedented move described by the United States as a historic gesture, Turkish Prime Minister Recep Tayyip Erdogan on Wednesday offered condolences over the massacres, calling them "our shared pain."