Late Tuesday, the Armenian army opened fire in the village of Alhanli in the southwestern Fuzuli region, killing a 2-year-old girl and a 50-year-old woman.

"The military attaches and journalists who visited the village saw that there was no headquarters or firing position belonging to the Azerbaijani army in the region, which proves that the main target of the Armenian army is civilians," Azerbaijan’s Defense Ministry said in a statement.

At the hospital, journalists and military attaches also visited Guliyeva Sarvinaz, another civilian who was wounded in the attack.

Military attaches and diplomats from Turkey, the U.S., Russia, Pakistan, China, South Korea, Kazakhstan, Ukraine, Georgia, Belarus, and Germany were also present during the visit.

Religious institutions in Azerbaijan sent letters to international institutions and organizations and religious leaders protesting the attacks on civilians.

The U.S. on Thursday voiced "deep" concern over Tuesday's attack and extended "heartfelt" condolences to the families of the victims.

"Along with OSCE [Organization for Security and Co-operation in Europe] Minsk Group co-chairs, we call upon the sides to cease military action and return to the negotiating table," State Department spokeswoman Heather Nauert told reporters. 

Nauert said the policy of the U.S. in the region is "clear," adding: "The only solution to this conflict is a negotiated settlement based on international law that includes adherence to the principles of non-use of force, territorial integrity, and self-determination."

The UN said it was also "increasingly" concerned with the deteriorating security environment in the region.

"We call upon the sides to refrain from any military action and strongly urge them to take immediate steps to de-escalate tensions and prevent further violence," Stephane Dujarric, spokesman for the secretary-general, told reporters on Thursday.

Dujarric said returning to the negotiating table in good faith is the "only" way to resolve "long-standing and dangerous" conflict.

On Wednesday, Turkey’s Foreign Ministry said the "atrocious" attack clearly shows that Armenian provocations using heavy weapons in border regions target civilians, especially woman and children, contrary to both international law and human values.

Azerbaijan and Armenia remain in dispute over the Upper Karabakh region, which a pro-Armenian militia invaded in 1993.

Three UN Security Council Resolutions and two General Assembly Resolutions refer to Upper Karabakh as part of Azerbaijan.

The Parliamentary Assembly of the Council of Europe refers to the region as being occupied by Armenian forces.

Anadolu Agency