Fighting has flared up again between Armenia and Azerbaijan over the region of Karabakh with deaths and injuries reported and the two countries trading barbs on Thursday.

Armenia accusing Azerbaijan of violating the fall 2020 agreement ending the 44-day Karabakh War is "nothing but mere hypocrisy," Azerbaijan's Foreign Ministry said on Thursday.

Azerbaijan has repeatedly pointed to Armenia's failure to meet the provisions of the Nov. 10, 2020 agreement signed by the two nations plus Russia, and especially how Armenian armed groups have not yet pulled out of Azerbaijan territories in Karabakh, said a ministry statement.

The ministry said under the tripartite agreement, "the peacekeeping contingent of the Russian Federation is deployed (in Karabakh) in parallel with the withdrawal of the Armenian armed forces."

In addition to ample evidence of the presence of illegal Armenian armed forces on the territory of Azerbaijan, this fact has also been acknowledged by Armenian officials, it said.

"We emphasize that the reason for the recent tension is the presence of illegal Armenian armed troops in the territories of Azerbaijan and provocations instigated by them. The bloody incident and killing of an Azerbaijani soldier on August 3 is precisely the result of Armenia's failure to fulfill its obligations," the statement read, referring to the flare-up on Wednesday.

Azerbaijan said it launched a retaliatory operation against Armenian forces in Karabakh after Armenia opened fire and killed an Azerbaijani soldier, according to its defense ministry.

"On the morning of Aug. 3, members of illegal Armenian armed detachments in the territory of Azerbaijan, where the Russian peacekeeping contingent is temporarily deployed, were subjected to intensive fire from the Azerbaijan Army positions stationed in direction of the Lachin region," the ministry said in a statement on Wednesday.

The retaliatory move comes after an Azerbaijani soldier was killed "as a result of the terrorist and sabotage action carried out by illegal Armenian forces this morning," it said.

The ministry said Azerbaijan "took relevant measures" and launched a counter operation after Armenian forces tried to seize the Kyrghgiz hill and establish new combat positions.

"As a result of the 'Revenge' retaliatory measure carried out by the Azerbaijani Army Units, the Girkhgiz peak, as well as Saribaba along the Karabakh ridge of the Lesser Caucasus and a number of other important heights were taken under control," it added.

The ministry also shared footage of the operation.

Need for deescalation

The violence drew immediate international reaction, with Russia accusing Baku of violating the brittle cease-fire and the European Union urging an "immediate cessation of hostilities."

"It is essential to de-escalate, fully respect the ceasefire and return to the negotiating table to seek negotiated solutions," a spokesperson for EU foreign policy chief Josep Borrell said in a statement.

"The European Union remains committed to help overcome tensions and continue its engagement towards sustainable peace and stability in the South Caucasus," Borrell's spokesperson added.

The U.S. similarly voiced that it is "deeply concerned" by fighting between Armenia and Azerbaijan, a State Department spokesperson said on the same day.

"We urge immediate steps to reduce tensions and avoid further escalation," State Department spokesperson Ned Price said in a statement.

Price called for "a negotiated, comprehensive, and sustainable settlement of all remaining issues related to or resulting from the Nagorno-Karabakh conflict."

Russia accused Azerbaijan of breaking the cease-fire and vowed to stabilize the situation.

"The cease-fire regime was violated by the armed forces of Azerbaijan around the Saribaba height," the Russian Defense Ministry said in a statement.

"The command of the Russian peacekeeping force, with representatives of Azerbaijan and Armenia, are taking measures to stabilize the situation."

The escalation came after Russian President Vladimir Putin spoke to Armenian Prime Minister Nikol Pashinyan on Tuesday.

Following Russia's intervention in Ukraine on Feb. 24, an increasingly isolated Moscow lost its status as the primary mediator in the Karabakh conflict.

Relations between the former Soviet republics of Armenia and Azerbaijan have been tense since 1991 when the Armenian military illegally occupied Karabakh, a territory internationally recognized as part of Azerbaijan, and seven adjacent regions.

Clashes erupted on Sept. 27, 2020, with the Armenian Army attacking civilians and Azerbaijani forces and violating several humanitarian cease-fire agreements.

During the 44-day conflict, Azerbaijan liberated several cities and around 300 settlements and villages that had been occupied by Armenia for almost 30 years.

The fighting ended with a Russian-brokered agreement on Nov. 10, 2020, which was seen as a victory for Azerbaijan and a defeat for Armenia.

In January 2021, the leaders of Russia, Azerbaijan and Armenia signed a pact to develop economic ties and infrastructure to benefit the entire region. It also included the establishment of a trilateral working group in Karabakh.

After the conflict ended, Azerbaijan launched a massive reconstruction initiative in the liberated Karabakh region.

In July, Azerbaijan began the process of returning its people to land recaptured from Armenian forces in what Baku calls "The Great Return." The oil-rich country has vowed to repopulate the recaptured lands.

President Ilham Aliyev had for years promised to recapture lands lost in the 1990s and the first returns marked a symbolic moment for Azerbaijan.