Authorities in Azerbaijan say a missile attack on the city of Ganja killed at least 12 people and wounded 40 others in early hours of Saturday.
Azerbaijan's Defense Ministry claimed that the cities of Ganja and Mingachevir were hit with missiles fired from two different locations in Armenia.
Armenian authorities have neither denied nor accepted the responsibility for the attacks on the two cities.
According to official sources in Azerbaijan, Saturday's missile attack destroyed at least 20 residential buildings in Ganja, the country's second-largest city.
The ongoing fighting between Azerbaijan and Armenia erupted on Sept. 27 and has killed hundreds of people, marking the biggest escalation of the decades-old conflict over breakaway region of Nagorno-Karabakh since a 1994 cease-fire.
The predominantly ethnic Armenian territory declared its independence from Azerbaijan in 1991 during the collapse of the Soviet Union, sparking a war that claimed the lives of as many as 30,000 people before a 1994 cease-fire. However, that independence is not internationally recognized.