During a phone call, Merkel and Russian President Vladimir Putin discussed other topics, as well, including the imprisonment of the Russian opposition figure Alexei Navalny.
What did the Kremlin say?
Following the call, the Kremlin also released a statement saying the two leaders had "expressed concerns over the escalation of tensions in the southeast of Ukraine."
"Vladimir Putin drew attention to the provocative actions of Kyiv, which has recently been purposefully exacerbating the situation on the front line," according to the statement.
The deputy head of Russia's presidential administration, Dmitry Kozak, was quoted by the TASS agency on Thursday as saying that any major military hostilities could mean "the beginning of the end of Ukraine." He argued that Russia would be forced to defend its citizens in eastern Ukraine.
What is the situation in Donbass?
Ukrainian President Volodymyr Zelenskiy was headed to Donbass on Thursday. He said he was "going to the locations of the escalation," adding that "Ukraine needs peace and will do everything for this."
Russia and Ukraine accuse each other of escalating tensions between Ukrainian forces and pro-Russia separatists. On March 26 alone, the Organization for Security and Cooperation in Europe (OSCE) recorded hundreds of ceasefire violations.
Ukraine's government has repeatedly called on Russia to pull its troops away from the border, with the Kremlin responding that internal troop movements are a domestic issue and arguing that it is entitled to protect Russian-speaking citizens in Donbass if the shaky ceasefire does not hold.
The European Union, NATO and the US have recently condemned the Russian military buildup on the border.