As tensions spill over in the South Caucasus, Azerbaijan’s Foreign Ministry said Wednesday it would not be attending a meeting with Armenia that was set for next Monday in Washington, D.C., condemning the U.S. for taking a “one-sided approach” to the conflict between the European countries. 

Armenian Prime Minister Nikol Pashinyan has been looking to ramp up peace talks between his country and Azerbaijan as the nations contend for the region of Nagorno-Karabakh. The 1,700-square-mile mountainous slice of land has been inhabited by Armenians for thousands of years, but it is surrounded by Azerbaijan, a majority Muslim nation that says the region is its territory. 

Azerbaijan was angered by testimony from U.S. Assistant Secretary of State for European and Eurasian Affairs James O’Brien, who spoke to the House Foreign Affairs Committee on Wednesday, Reuters reported. The country said O’Brien’s remarks were “one-sided and biased” after the assistant secretary of state discussed Azerbaijan’s take over of Nagorno-Karabakh in September, which forced more than 100,000 Armenians to flee their homes in what has escalated to ethnic cleansing of the Christian population from the oldest Christian nation in the world. 

During the hearing, O’Brien told the committee that the U.S. government has “urged Azerbaijan to ensure all ethnic Armenians who have departed Nagorno-Karabakh are guaranteed a safe, dignified, and sustainable return, should they so choose, with their rights and security guaranteed.” 

“We have also called for Azerbaijan to respect and protect the cultural heritage of the many groups who have lived in the region throughout the millennia,” O’Brien said, adding, “Our message to Armenia and the displaced has been unambiguous: The United States will support Armenia’s sovereignty, territorial integrity, and democratic institutions.”

Azerbaijan’s Foreign Ministry claimed that O’Brien’s testimony left out important context in the conflict. Azerbaijan accused Armenia of refusing to respond to peace negotiations “for more than two months” and claimed Armenia was “illegally stationing” more than 10,000 troops in Nagorno-Karabakh before Azerbaijan’s takeover. The country also said U.S. officials are unwelcome in Baku, Azerbaijan’s capital. 

The Muslim country’s bombardment of Nagorno-Karabakh in September was preceded by a military blockade that began last December, which cut off access to food, electricity, and water from the outside. Yana Avanesyan, a doctoral researcher who is originally from Nagorno-Karabakh, told The Daily Wire last month that the religious difference between the two countries plays a major role in the Armenia-Azerbaijan conflict.

“When we say Armenians, we are speaking about us being Christians,” Avanesyan told The Daily Wire. “We know they hate us so much that they will just destroy everything.” 

The U.S. has taken a clear stance in the conflict, condemning Azerbaijan for its recent actions in Nagorno-Karabakh. 

“Azerbaijan’s use of force in Nagorno-Karabakh has eroded trust and raised doubts regarding Baku’s commitment to a comprehensive peace with Armenia,” O’Brien said. “Given this new reality, the Department has made it clear to Azerbaijan that there cannot be ‘business as usual’ in our bilateral relationship. The United States has condemned Azerbaijani actions in Nagorno-Karabakh, canceled high-level bilateral meetings and engagements with Azerbaijan, and suspended plans for future events.”