Image copyright Reuters Image caption Mortar bombs fell in the area
A huge fire has broken out on the border between Armenia and Azerbaijan.
The Armenian defence ministry has put the death toll at eight and says four servicemen were wounded in the incident.
Azerbaijan’s national security council, meanwhile, said there were no casualties.
The clash is the latest in a conflict that flared last year when both countries began claiming they had put an end to the conflict that had been holding since 1991.
How did it start?
Armenia announced last year that it had ended hostilities with Azerbaijan, on the grounds that the two sides had switched their zones of control around a group of disputed mountains.
Azerbaijan however said that the border had remained unchanged and that any victory was achieved only through war.
Last April an Armenian soldier was killed, followed by an Azerbaijani soldier in September, and in November a civilian was killed.
When does the next conflict break out?
In December, Azerbaijan and Armenia both claimed victory in a major border clash – which saw a large firefight between their forces and an Azerbaijani volunteer battalion.
“A unit of the Azeri volunteer battalion ‘Bulleit’ [Bullets or Bakeid] resorted to shelling and fired mortar shells into the Armenian territory near the Baku-Armenian border,” the Azerbaijan security council said.
The office of the Armenian president, Armen Sarkissian, said some 150 mortar bombs were fired by the Azeri battalion at Armenian positions. The ceasefire was called in the morning, after 30 people were injured.
This is the conflict in its broadest definition. Azeri and Armenian troops remain engaged in active war under a 1994 peace deal, which technically ended the war, but it has never stopped.
Armenia, Armenia and Azerbaijan are landlocked ex-Soviet states, and after independence both failed to carve out separate states.
Neither country would really want to return to war, but land issues remain on their agenda.
What are the options for resolving the conflict?
Both Armenia and Azerbaijan have unresolved territorial disputes with ethnic groups that make up roughly a third of the total population of their neighbours.
Both nations see each other as their core allies. Armenia would like to recapture the territory they lost to Azeri forces in the First and Second Armenian Revolutions, and recognises the Armenian territory of Nagorno-Karabakh in Nagorno-Karabakh, and the other city of Stepanakert in Azerbaijan.
The conflict between the two countries has claimed the lives of approximately 30,000 people, and devastated the region for decades.
Azerbaijan has always claimed Nagorno-Karabakh as a distinct and independent nation, with which they never fought a war.
The former British and United Nations under-secretary general for human rights, Louise Arbour, called on both Azerbaijan and Armenia to resolve their differences through talks, rather than force.
“It is clear that time is an increasingly insufficient ally for the people of the Nagorno-Karabakh region and the wider region, as winter approaches,” she said at the time.
“I call on all sides in the conflict to take advantage of the goodwill of the international community and the time at hand to seize the opportunity to build confidence and resolve conflict issues through negotiation,” she added.
However, the recent escalation of hostilities means negotiations are looking increasingly likely.