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.

Azerbaijani forces killed an ethnic Armenian serviceman from the disputed Nagorny Karabakh region's army in the latest outburst of violence between the foes, the separatist region's defense ministry said Monday.

The Karabakh army's "lieutenant colonel Garik Balayan was killed on May 25 (Sunday) on the southern sector of the line of separation between Azerbaijani and Karabakh forces," the Karabakh defense ministry said in a statement.

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. 

A court in Azerbaijan on Thursday sentenced a prominent opposition journalist to eight years in prison on charges his lawyer dismissed as trumped up and politically motivated.

Perviz Hashimli -- a reporter at opposition newspaper Bizim Yol –- "was sentenced to eight years in prison on trumped-up charges of illegal possession and trafficking of weapons," his lawyer Elchin Sadykhov told Agence France Presse.

French President Francois Hollande said in Azerbaijan Monday that cooperation between Europe and ex-Soviet countries should not be seen as infringing on anyone else's interests, a clear reference to Moscow amid the crisis in Ukraine.

"The European Union's Eastern Partnership is not directed against anyone, but should encourage greater trade and investment", the French leader said after meeting with Azerbaijani counterpart Ilham Aliyev.

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.

Azerbaijan charged a prominent journalist on Monday with spying for its arch-foe Armenia and ordered him to spend three months in pre-trial detention.

Azerbaijan's prosecutor general's office said in a statement that Rauf Mirkadyrov had been charged with high treason after he "was recruited by the Armenian secret services in 2008 and supplied Yerevan with information on Azerbaijan's state secrets".

A prominent newspaper journalist from Azerbaijan has been arrested on suspicion of espionage after being deported from Turkey, his lawyer told Agence France Presse on Sunday.

Rauf Mirkadyrov was detained in Baku, the capital of the ex-Soviet country, and is now being investigated for espionage, his lawyer Fuad Agayev said.

A court in Azerbaijan on Monday sentenced two leading opponents of strongman President Ilham Aliyev to seven and five years in jail in a decision U.S. officials slammed as "politically motivated".

Opposition Republican Alternative (REAL) movement leader Ilgar Mammadov was sentenced to seven years imprisonment and Tofig Yagublu, deputy chairman of the anti-government Musavat party, was handed a five-year term over allegations they incited anti-government riots last year, a REAL spokesperson told AFP.

Armenian forces on Wednesday killed an Azerbaijani soldier at the volatile border between the two foes locked in a protracted conflict over the disputed Nagorny Karabakh region, officials in Baku said.

"Junior Sergeant Kerem Nokhbalayev has been killed on February 26 (Wednesday) as a result of ceasefire violation by Armenia," Azerbaijan's defense ministry said in a statement.