Azerbaijan has expressed regret over the death of an Armenian officer allegedly killed by an Azeri colleague.
Ramil Safarov is accused of attacking Gurgen Markarian with an axe as he slept in his dormitory in Budapest, where they were on a Nato course.
Hungarian police who arrested the Azerbaijani lieutenant say they are still investigating the motive.
But Azeri and Armenian officials are blaming the death on tensions created by their war in the early 1990s.
The Azerbaijani foreign ministry expressed its condolences on Friday to the dead man's family and colleagues.
The ministry statement also said it understood the Armenian officer had made insulting statements to Mr Safarov about the war in Nagorno-Karabakh, which had affected his emotional state.
It said several of Mr Safarov's relatives were killed in the war and his family had to flee when their home was taken by Armenian forces.
They still live in a student dormitory in Azerbaijan's capital, Baku.
The ministry appealed to Armenia to show restraint, and said the killing should not cause any further deterioration in relations between Armenia and Azerbaijan.
'Hysteria and propaganda'
The Armenian foreign ministry said earlier that the killing was the result of anti-Armenian hysteria and propaganda in Azerbaijan.
Both Mr Safarov, 27, and Mr Markarian, 26, were studying on a course run under the auspices of Nato's Partnership for Peace programme.
Azerbaijanis and Armenians fought a bitter war in the region following an independence declaration by Armenian-backed forces in the Azerbaijani enclave of Nagorno-Karabakh.
About 30,000 people died, and over one million civilians fled their homes in six years of fighting.
Azerbaijani and Armenian-backed forces agreed a ceasefire in 1994, but no peace deal has been signed.
Clashes occasionally break out on the border.