Armenia denied the attack but leader of Nagorno-Karabakh said it targeted Ganja on Sunday.
Azerbaijan’s foreign ministry says one civilian has been killed and four wounded in an Armenian rocket attack on the Azerbaijani city of Ganja on Sunday.
Armenia denied attacking its neighbour. The leader of Nagorno-Karabakh, a breakaway region in Azerbaijan controlled by ethnic Armenians, said it had targeted Ganja, a city of more than 330,000 in the western part of the country.
In statements posted on its website earlier, Azerbaijan’s defence ministry said Ganja and several other civilian areas were being attacked using rockets and shelling.
“Azerbaijan will destroy military targets directly inside Armenia from which shelling of its population centres is taking place,” presidential aide Hikmet Hajiyev said adding that there were civilian casualties in Beylagan, which borders Nagorno-Karabakh.
Al Jazeera’s Sinem Koseoglu, reporting from Ganja, said: “People here are telling us that approximately an hour after a rocket landed, a second hit another residential area a few blocks away, wounding two people.”
Earlier, Armenian officials said Azerbaijan’s forces had shelled Stepanakert, Nagorno-Karabakh’s main city, where the sound of sirens was heard at approximately 9:30am (05:30 GMT), followed by several explosions, according to AFP news agency.
“Azerbaijani forces are shelling civilian targets in Stepanakert with rockets,” Armenian defence ministry spokesman Artsrun Hovhannisyan told AFP.
Azerbaijani authorities said they had taken “retaliatory measures” after rocket fire from Stepanakert.
Al Jazeera’s Bernard Smith, reporting from Stepanakert, said the city has been under intense bombardment since the morning.
“There has been considerable damage on the buildings in the city centre,” he said. “People were unable to go out. They are hiding in the bomb shelters. Civilians are on the receiving end of this bombardment.”
Separately, the defence ministry in Baku said Armenian armed forces were firing rockets at the towns of Terter and Horadiz in the Fizuli region.
Nagorno-Karabakh is controlled by ethnic Armenians backed by Armenia and has been the subject of several United Nations resolutions calling for an end to the occupation of Azeri lands.
The leader of the breakaway province, Arayik Harutyunyan, said he was heading to the front and that the “final battle” for the region had begun, while Armenian Prime Minister Nikol Pashinyan said his nation was facing a historic threat.
“We are facing possibly the most decisive moment in our millennia-old history,” Pashinyan said in an address to the nation on Saturday. “We all must dedicate ourselves to a singular goal: Victory.”
Azerbaijan and Armenia previously fought a war over Nagorno-Karabakh in the late 1980s and early 1990s as they transitioned into independent countries amid the collapse of the Soviet Union.
The war, which ended with a fragile peace treaty in 1994, is estimated to have killed tens of thousands of people, including more than a thousand civilians.
Armenia says it was Azerbaijan that restarted the conflict by launching a major offensive on September 27, while Baku says it was forced to respond to provocations by the other side.
The fighting continued despite international calls for the neighbours to halt clashes and begin talks as fears grow that the fighting could expand into a multi-front war sucking in regional powers Turkey and Russia.