Azerbaijani President Ilham Aliyev confirmed in a televised address to the nation that the country's forces have taken control of a key city in the contested Nagorno-Karabakh region.

Aliyev said that Azerbaijani military forces had now occupied the city of Shusha.

Aliyev's announcement was greeted with jubilation on the streets of Baku with thousands of waving flags. Armenian officials responded to the claims, denying that Azerbaijani forces had captured the city.

"[This day] will become a great day in the history of Azerbaijan. Shusha is ours - Karabakh is ours," Aliyev said during his televised address.

Azerbaijan's close ally, Turkey, publicly congratulated the country. Turkish President Recep Tayyip Erdogan said in a public gathering in the country's north-west province of Kocaeli that he believed Azerbaijan is now one step closer to liberating its lands.

"I congratulate my Azeri brothers' Shusha victory...I believe [it] is a sign that the rest of the occupied lands will be liberated soon too," Erdogan said.

Armenia's defense ministry and Nagorno-Karabakh officials claimed that Azerbaijan's proclamations were false and that the city of Shusha remains an "unattainable pipe dream." Officials also claimed that the city had so far withstood Azerbaijan's assaults.

Shusha is the second-largest settlement in the contested Nagorno-Karabakh region. It is a strategic location given its proximity to the main corridor that connects both countries. The city is also an important spiritual center for people living on both sides of the border.

Since fighting erupted in late September, more than 5,000 civilians and soldiers have been killed. Azerbaijani forces allegedly launched the offensive to reclaim Nagorno-Karabakh. The region is internationally recognized as part of Azerbaijan's territory. Since the war between the two former neighbors ended in 1994, Armenians have mostly been occupying the area.

In the background, the conflict has resulted in increased tensions between Turkey and Russia. Turkey is allied with Azerbaijan, while Russia has a military pact with Armenia. Turkey has expressed its full support of Azerbaijan's fight to retake its territory, while Russia is hesitant to back Armenia if it chooses to take the fight beyond its borders.