Nagorno-Karabakh broke away from Azerbaijan with Armenian support after a bloody post-Soviet ethnic conflict in the early 1990s. In 2020, Azerbaijan successfully regained part of the territory controlled by the separatists. Under the terms of a subsequent ceasefire, Russian peacekeepers were deployed to protect the rest of the territory held by the separatists. However, both sides accuse each other of violations and in recent days violence has flared up. Sign up now for FREE unlimited access to Reuters.com Register Azerbaijan’s defense ministry said Armenia flagrantly violated the ceasefire by committing an act of sabotage that killed a soldier. In addition, Baku said its forces had foiled an attempt by Armenians to seize a hill in an area controlled by Russian peacekeepers. “As a result, those fighting for the illegal Armenian armed formations were killed and injured,” it said in a statement, calling on all Armenian troops to withdraw from the area and promising “crushing” countermeasures if necessary. In response, Armenia’s foreign ministry said Azerbaijan violated the ceasefire by launching an attack on areas controlled by peacekeepers. In a statement, it said that Yerevan wants the international community to “take measures to stop Azerbaijan’s aggressive behavior and actions”. The European Union called for an immediate end to hostilities and said both sides should respect the ceasefire, a call echoed by the Polish president of the Organization for Security and Cooperation in Europe. Earlier, the separatist authorities in the ethnically Armenian enclave declared a partial mobilization. Russia said the situation in areas controlled by its peacekeepers was becoming more tense and reported at least one ceasefire violation by Azeri forces, Interfax reported. Sign up now for FREE unlimited access to Reuters.com Register Reporting by Nailia Bagirova, writing by David Ljunggren. edited by Bernadette Baum and Alistair Bell Our Standards: The Thomson Reuters Trust Principles.