Azerbaijan said Friday one of its soldiers had been shot dead by Armenian forces along the volatile border between the foes who are locked in a decades-long feud over the disputed region of Nagorny Karabakh.

"(Azerbaijani) army servicemen Eshgin Guliyev died as a result of a ceasefire violation on Thursday," Azerbaijan's defense ministry said in a statement.

Armenia has arrested a former police colonel following allegations he was trying to pass on military secrets to arch-foe Azerbaijan, the country's intelligence agency said on Wednesday.

Ex-police officer Khachik Martirosyan, 57, was detained last Friday after purportedly contacting Azerbaijani officials with the offer of spying on his ex-Soviet homeland in return for money, the National Security Service said.

Azerbaijani forces say they have captured an Armenian spy following the latest in a series of tit-for-tat raids along the volatile frontier between the two arch-foes.

"There was an attempt by an Armenian reconnaissance and sabotage group to cross the border in the Tovuz region (northwestern Azerbaijan) on January 28," the defense ministry in Baku said in a statement released late Tuesday.

Armenian forces on Monday shot dead an Azerbaijani soldier in the latest uptick of border violence along the disputed Nagorny Karabakh frontier, the defense ministry in Baku said.

The fatal shooting came barely a week after Baku said that another Azerbaijani soldier was killed along the volatile frontline by Armenia troops, as both sides accused each other of launching tit-for-tat cross-border raids.

Armenian troops Thursday killed an Azerbaijani soldier in the latest in a week of tit-for-tat clashes over the disputed region of Nagorny Karabakh, Azerbaijan's defense ministry said.

Captain Elnur Jafarov was killed "as a result of a violation of the ceasefire by the Armenian side" along the volatile frontline in the southwestern Tatar region, some 270 kilometers (160 miles) from the Azerbaijani capital Baku, the defense ministry said.

Azerbaijan on Wednesday said it had repelled a cross-border raid by Armenian forces in the latest outbreak of violence over the disputed Nagorny Karabakh region.

"During the night an Armenian commando reconnaissance team tried to cross the line of contact in the southwestern sector of the frontline," Azerbaijan's defense ministry said in a statement.

Azerbaijani forces on Monday killed an ethnic Armenian soldier in an alleged cross-border raid into Nagorny Karabakh, officials from the Armenian-backed breakaway region said.

Defense forces soldier Armen Hovhannisyan died from gunshot wounds after a clash with an "Azerbaijani subversive intelligence party" trying to cross into the territory early Monday, a statement from the region's defense ministry said.

Azerbaijani authorities have arrested the head of an independent election monitoring group after it criticized presidential polls that secured a new term for strongman Ilham Aliyev, one of his colleagues said Tuesday.

A Baku court on Monday ordered Anar Mammadli, chairman of the Election Monitoring and Democracy Studies Center (EMDS), to spend three months in pre-trial detention in connection with an investigation into alleged tax evasion.

Azerbaijani troops killed an Armenian soldier in a fresh clash along the volatile border between the two bitter rivals, the Armenian government said on Monday.

Hrant Pokhosyan, 26, was killed on Saturday when his convoy came under attack at a northeastern sector of the border, Armenia's defense ministry said.

A court in Azerbaijan on Monday jailed another 10 people on charges of plotting attacks during the Eurovision Song Contest hosted last year by the ex-Soviet state.

A source at the court for serious crimes in the capital Baku told Agence France Presse they were sentenced to jail terms of three to 10 years.