The early hours attack, which also saw a strike on the nearby strategic city of Mingecevir, came hours after Azerbaijani forces shelled Stepanakert, the capital of the ethnic Armenian separatist region.

The explosions in Ganja levelled a row of houses and left more than 45 people injured in an attack Aliyev described as "a war crime".

He said his army would "take revenge on the battlefield" and promised to capture Karabakh by driving out Armenian forces "like dogs".

Prosecutors said that as the result of the attack on Ganjia 13 people died including small children.

Armenia and Azerbaijan had last Saturday agreed to a ceasefire after 11 hours of talks in Moscow, but then both accused each other of violating the deal.

On Saturday evening, Russian Foreign Minister Lavrov held phone talks with his counterparts from Armenia and Azerbaijan and stressed "the need to strictly follow" the Moscow agreement, the foreign ministry said.

The ministers also confirmed the importance of beginning "substantive" talks to settle the conflict, the ministry in Moscow said.

- 'Our pain is deep' -

As the sun rose over the devastation in Ganja, Mayil Shakhnazarov, 36, said it was impossible to identify some of those killed.

"What can we say? Our pain is deep. Really deep," he told AFP.

The seeming tit-for-tat attacks further undermine international efforts to calm a resurgence of fighting between Christian Armenians and Muslim Azerbaijanis and avoid drawing regional powers Russia and Turkey into a conflict that has already killed hundreds of people.

An AFP team in Ganja saw rows of houses turned to rubble by the strike, which shattered walls and ripped roofs off buildings in the surrounding streets.

People ran outside in shock and tears, stumbling through dark muddy alleys in their slippers, some wearing bathroom robes and pyjamas.

- 'Everything shattered' -

The EU condemned the strike on Ganja and said the ceasefire deal "must be fully respected without delay".

"The European Union deplores the strikes on the Azerbaijani city of Ganja," said a spokesperson for EU foreign affairs chief Josep Borrell

"All targeting of civilians and civilian installations by either party must stop."

The attack came six days after a missile struck another residential part of the city of more than 300,000 people, killing 10 civilians and leaving many on edge.

At the scene of the latest strike, Durdana Mammadova, 69, was standing on the street at daybreak because her house was destroyed.

"We were sleeping and suddenly we heard the blast. The door, glass, everything shattered over us," she said.

Nagorno-Karabakh's military said Azerbaijani forces had stepped up their attacks on Friday across the front, shelling Stepanakert and a nearby town.

On Saturday, Karabakh separatist leader Arayik Harutyunyan said "intensive fighting" continued "along the entire line of defence".

- Complicit in 'savagery' -

Turkey, a staunch ally of Azerbaijan and widely accused of supplying mercenaries to bolster Baku's forces, said the strikes were a war crime and called on the international community to denounce them.

"Armenia continues to commit war crimes and massacre civilians. To remain silent in the face of this savagery is to be complicit in these crimes," Turkish Foreign Minister Mevlut Cavusoglu said on Twitter.

The Armenian defence ministry tweeted following the attack a list of what it described as "legitimate targets" in Ganja, including an ammunition factory.

At around the same time in the city of Mingecevir, an hour's drive north of Ganja, AFP heard the impact of a huge blast that shook buildings.

Mingecevir is protected by a missile defence system because it is home to a strategic dam.

The defence ministry said Mingecevir had come "under fire", but provided no other immediate details.

An Azerbaijani official said another missile hit a separate industrial district of Ganja at around the same time.

- Hundreds killed -

The long-simmering conflict between Armenia and Azerbaijan erupted again on September 27 and has so far killed more than 700 people, including nearly 80 civilians.

The mountainous western region of Azerbaijan has remained under separatist Armenian control since a 1994 ceasefire ended a brutal war that killed 30,000.

Armenia, which backs Nagorno-Karabakh but does not recognise its independence, has admitted that Azerbaijani forces have made important gains along the front in the past week.

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