Azerbaijan and Armenia again crossed swords before the U.N.'s top court on Monday, with Baku asking the court to throw out a case brought by Yerevan accusing it of ethnic cleansing and allegedly violating a U.N. anti-discrimination treaty.

The case, a part of the fallout from decades of confrontation between the South Caucasus rivals, comes as military tensions are again ramping up between the neighbors following the conflict in Azerbaijan's region of Karabakh.

The tensions erupted into a 2020 war that left more than 6,600 people dead in the region, which is within Azerbaijan but had been under the illegal occupation of ethnic Armenian separatists backed by Armenia since the end of a separatist war in 1994.

Baku's forces liberated the mountainous region in September, prompting most of its 120,000 residents to flee to Armenia.

Tit-for-tat lawsuits

Armenia first filed the discrimination claim in the International Court of Justice (ICJ) – also known as the World Court – two years before that in 2021, accusing Azerbaijan of breaching the Convention on the Elimination of All Forms of Racial Discrimination (CERD).

The case accused Azerbaijan of glorifying racism against Armenians, allowing hate speech against Armenians and destroying Armenian cultural sites – all accusations that Baku denies.

Azerbaijan subsequently filed a claim against Armenia, accusing it of discrimination and ethnic cleansing against Azerbaijanis and breaching the same treaty.

On Monday, Azerbaijani Deputy Foreign Affairs Minister Elnur Mammadov told the court that most of Armenia's complaints related to the armed conflicts over Karabakh and did not fall within the scope of the anti-discrimination treaty.

He also accused Armenia of not genuinely engaging in negotiations before bringing the case to court. CERD has a clause allowing disputes to be resolved by the World Court if bilateral negotiations fail to broker a settlement.

"Armenia's application misuses the (treaty) and tries to escape its obligation to attempt settlement of its dispute with Azerbaijan by way of negotiation before invoking the court's jurisdiction," Mammadov said.

There were "limited negotiations" but Yerevan "failed to pursue them," Mammadov said.

"From the outset, Armenia had its sights firmly set on commencing these proceedings before the court ... and using the fact of these proceedings to wage a public media campaign against Azerbaijan," Mammadov said.

International law professor Stefan Talmon, representing Azerbaijan, added that Armenia "never gave negotiations a chance."

He said that "with no negotiations and no genuine attempt at negotiations, that basically is the end of Armenia’s application" to the court.

Azerbaijan also argued that most allegations in Armenia's case fall outside the scope of the discrimination convention, meaning the court did not have jurisdiction.

Armenia will respond to the Azerbaijani objections on Tuesday.

Both states have filed legal objections to the other's case, which will be heard in the coming two weeks.

In November last year, the court issued emergency measures in Armenia's case ordering Azerbaijan to allow ethnic Armenians who fled Karabakh in September to return.

Armenia accuses Azerbaijan of ethnic cleansing. Azerbaijan says it has pledged to ensure all residents’ safety and security, regardless of national or ethnic origin, and that it has not forced ethnic Armenians to leave Karabakh.

The ongoing hearings will cover only the legal objections to the jurisdiction of the ICJ and will not go into the merits of the discrimination claims. A final ruling in both cases can be years away and the ICJ has no way to enforce its rulings.

Peace negotiations

The 2020 conflict ended with a Russia-brokered cease-fire agreement that granted Azerbaijan control over parts of Karabakh as well as some adjacent territories under illegal Armenian occupation.

Villages on both sides were destroyed and the mountainous region has been littered with countless landmines in the conflict's aftermath.

In December, the two sides agreed to begin negotiations on a peace treaty. Key elements in securing a treaty are demarcating borders and establishing regional transport corridors through each other's territory.

They have since held numerous talks, including two days of negotiations in Berlin in February. However, many residents of Armenia’s border regions have resisted the demarcation effort, seeing it as Azerbaijan encroaching on areas they consider their own.

Azerbaijan specifically wants Armenia to return four villages it says Yerevan is occupying, which are important for Armenia as they control its main road northwards to the border with Georgia.

Armenia’s prime minister said last month that the Caucasus nation needs to define its 1,000-kilometer (620-mile) border with Azerbaijan quickly to avoid a new round of hostilities.

Border tensions have been steadily increasing between the sides in the meantime, as recently as last week when they traded accusations of firing on each other’s military positions.

The conflict has also strained ties between Russia and ex-Soviet Armenia, with Yerevan considering that Moscow did not do enough to help when it was under attack.

In February, Armenia formally joined the International Criminal Court (ICC), despite Moscow warning against the move.

It is now obliged to arrest Russian President Vladimir Putin if he sets foot on Armenian territory under an ICC arrest warrant issued for the Russian leader in March 2023.