UN Secretary General Antonio Guterres has called for an immediate end to fighting in the disputed territory of Nagorno-Karabakh, where Armenia has accused Azerbaijan of ethnic cleansing.
Mr Guterres called in the "strongest terms for an immediate end to the fighting, de-escalation and stricter observance of the 2020 ceasefire", said his spokesman Stephane Dujarric.
The EU, US, France and Russia have all appealed for calm in the disputed region, home to a majority ethnic Armenian population but internationally recognised as part of Azerbaijan.
Dozens have been killed and more than 7,000 evacuated from their homes in the latest fighting after Azerbaijan said it began a counter-terrorism operation in the region.
Baku's Defence Ministry said its military operation was continuing "successfully" on Wednesday, despite calls from Washington to stop the violence.
After months of rising tensions, Azerbaijan this week sent in troops backed by artillery strikes in an attempt to bring the breakaway region to heel.
Moscow, which acts as peacekeeper between the two, urged "the conflicting parties to immediately stop the bloodshed, stop hostilities and eliminate civilian casualties", Russia's Foreign Ministry said on Wednesday.
Armenia and Azerbaijan have fought two wars over the region, in the 1990s and in 2020.
On Tuesday, US Secretary of State Antony Blinken spoke by phone with the leaders of both Armenia and Azerbaijan, with French President Emmanuel Macron also speaking to Armenian Prime Minister Nikol Pashinyan.
Mr Blinken urged Baku "to cease military actions in Nagorno-Karabakh immediately and de-escalate the situation" in a call with President Ilham Aliyev, State Department spokesman Matthew Miller said.
Azerbaijan's presidency has said Armenia "must raise the white flag" or fighting with separatists will continue.
