The strike, which came hours after a shelling attack on the Nagorno-Karabakh capital Stepanakert, marked a new escalation in the three-week conflict between ethnic Armenians and Azerbaijanis over the separatist region.

An AFP team in Ganja saw a block of buildings turned to rubble, with people fleeing the scene in tears, some wearing bathroom robes and pajamas, and many still in their house slippers.

Dozens of rescuers in red helmets struggled to find survivors with their bare hands in the dark as clouds of dust lifted from the site.

A few hours into their search, one team brought black bags containing body parts into an ambulance, including a head and an arm.

The missile struck in the early hours of Saturday while most residents were asleep.

Hikmat Hajiyev, an assistant to Azerbaijan President Ilham Aliyev, tweeted that according to "initial information, more than 20 houses were destroyed".

Another residential district of Ganja was hit by a missile that killed 10 civilians last Sunday.

- Calls for silence -

The rescuers called for silence so that they could detect sounds of survivors, and pulled out passports, unopened delivery packages, and items of clothing from the debris.

One witness sad he he saw a small child, two women and four men pulled from the rubble, although their condition was not immediately clear.

"One woman was missing her feet. Someone else was missing an arm at the elbow," said Elmir Shirinzaday, 26.

AFP later saw three more people carried away on stretchers, although it was no clear if they were dead or alive.

"My wife was there, my wife was there," one man cried inconsolably while being walked toward an ambulance by a paramedic.

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, and it was not immediately clear if the missile was destroyed in the air or had made impact.

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

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

No immediate details about that second attack were known.

The decades-long Nagorno-Karabakh conflict re-erupted on September 27 in hotly disputed circumstances, threatening to draw in regional powers Russia and Turkey.

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

The current escalation is the deadliest and longest since that war.

The shelling of Stepanakert and the strikes on Ganja followed a joint call from Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan on Wednesday to "end the bloodshed as soon as possible."