There are fights in Nagorno-Karabakh, which makes people worry about another war.
On Tuesday, the leader of Armenia said that at least 49 of his country's soldiers had died in fighting with the Azerbaijani Army overnight. It was the worst escalation of fighting between two countries since the 2020 war over Nagorno-Karabakh, a disputed mountain enclave, and a threat to both a loyal Russian ally and a cease-fire that Russia negotiated.
The fighting started early on Tuesday, and both sides blamed the other for it. It was the start of the armed conflict that has been going on for decades over Nagorno-Karabakh, which is part of Azerbaijan but claims independence and is close to Armenia.
As things have gotten worse between the two former Soviet states in the South Caucasus, fears have grown that Russia could get into a second war on top of its invasion of Ukraine. Some military experts thought that Russia's recent losses in northeastern Ukraine may have given Azerbaijan more confidence.
Prime Minister Nikol Pashinyan told Armenia's Parliament that fighting had become less intense, but that Azerbaijan was still attacking on one or two fronts. This is according to a statement on the Parliament's website.
In a statement on its website, the defense ministry of Azerbaijan said that Armenia had done a number of "large-scale provocations" that forced it to respond. Mr. Pashinyan denied that his country had done anything to start trouble and said that Azerbaijan had attacked Armenian land.
He got Armenia's Security Council together, and they decided to ask for help from Russia. Russia and Armenia are both members of the C.S.T.O., a military alliance that is led by Russia and says that an attack on one member would be seen as an attack on all. Armenia is another place where Russia has a military base.
In Moscow, Russia's foreign ministry asked both sides to be calm and follow the agreements that ended the 2020 war. It also said that it had negotiated a new cease-fire that would start at 9 a.m. Wednesday.
In 2020, after Azerbaijan went to war to get back some of the land it had lost in another war that began with the fall of the Soviet Union in the late 1980s, Russian President Vladimir V. Putin helped sign a broad cease-fire.
Moscow has been trying to find a balance between Yerevan and Baku for years, but as the war in Ukraine has forced the Kremlin to focus its attention and power elsewhere, this has become a harder and harder task.
As part of the agreement, Mr. Putin sent about 2,000 peacekeeping troops to the area. This showed that Russia has a strong role as a mediator in the Caucasus, which has been troubled by war and instability for decades.