Azerbaijani and Armenian forces on Wednesday said they were largely observing a truce that halted four days of clashes which claimed scores of lives in the worst outbreak of violence in decades over the disputed Nagorny Karabakh region.

"The ceasefire was largely observed overnight along the Karabakh frontline," the Armenia-backed separatist defense ministry in Karabakh said in a statement.

Azerbaijani President Ilham Aliyev on Thursday freed 14 jailed rights activists and opposition politicians in an amnesty, a move welcomed by the European Union and rights activists.

The move was part of a broader amnesty that saw a total of 148 inmates pardoned, a decree released by Aliev's office said.

An Azerbaijan court on Tuesday sentenced an opposition politician to three years in jail over hooliganism charges he claims are fabricated and politically motivated.

Mamed Ibragim, one of the leaders of the opposition Popular Front party, "rejects the charges as false and believes he is being punished for his political activity," his lawyer Yalchin Imanov, told AFP.

Azerbaijan has arrested eight men for fighting alongside the Islamic State group in Syria and Iraq, the majority-Muslim Caucasus nation's authorities said on Friday.

The men, all Azeri nationals, "were trained in Islamic State training camps in 2012-2015 and took part in fighting in Syria and Iraq within the ranks of terrorist groups," the national security ministry said in a statement.

A court in ex-Soviet Azerbaijan has sentenced an activist of the opposition People's Front party to eight years in jail for disobeying police, a charge he denounced as politically motivated.

Zeynal Bagirzada "was jailed on Wednesday for eight years," the activist's brother Yashar Bagirsoy told AFP on Thursday, adding: "He insists that he is being persecuted because of his political activism."

Hit hard by falling oil prices, ex-Soviet Azerbaijan has plunged into an economic crisis that has seen rare protests shake the authorities in the tightly-controlled nation.

Over the last week, violent clashes broke out between riot police and thousands of demonstrators who took to the streets in cities across the energy-rich Caspian nation to express their discontent against price hikes and unemployment.

Azerbaijan has arrested 55 protesters, officials said Thursday, after police used tear gas to disperse anti-government rallies across the energy-rich country hit hard by falling oil prices.

Mass protests gripped the ex-Soviet Caspian nation earlier this week amid swelling discontent over price hikes and the collapse of the national currency.

Azerbaijan has arrested a prominent opposition leader on charges of inciting racial and religious hatred that risk up to five years in prison, his party said on Wednesday.

Fuad Gahramanly, deputy chairman of the Popular Front, was arrested Tuesday night and "accused of inciting racial and religious hatred with the use and threat of violence," party chairman Ali Karimly told AFP.

Two policemen and four alleged members of a radical Islamist group have been killed in a shootout during a raid in Azerbaijan, the interior ministry said Thursday.

The suspects opened fire when police attempted to arrest "leaders of an unregistered radical Islamist group," the ministry said in a statement.

Azerbaijani sharpshooters have shot dead two ethnic Armenian soldiers of the breakaway Nagorny Karabakh's army, separatists said Friday, in the latest clash over the disputed enclave.

"On November 12, two Karabakh army servicemen were killed by Azerbaijani snipers at the southern sector of the Karabakh frontline," the rebel defense ministry said in a statement.