Azerbaijian has announced a "unilateral ceasefire" after clashes with Armenian troops over the disputed Nagorno-Karabakh region. But it threatened to strike back if it came under attack.

Azerbaijan said it would "reinforce" several strategic positions it had "liberated" inside the region, which is controlled by Armenia. A spokesman for the rebel defense ministry in Karabakh disputed the ceasefire announcement, saying fighting had not halted along the frontline.

Both Azerbaijan and Armenia have blamed the other for the clashes which began on Saturday night. Azerbaijan said a dozen of its soldiers were killed. Armenian says it has lost at least 18.