The ceasefire is due to take effect at 8 a.m. local time (0400 GMT) on October 26, the US State Department and the governments of Azerbaijan and Armenia said in a joint statement hours after a new fighting erupted between the two countries forces.
The United States has said a new humanitarian ceasefire will take effect on Monday in the conflict between Azerbaijan and Armenia over the occupied Nagorno-Karabakh, even as fresh fighting erupted between the two sides who blame each other for the failure of previous truces.
The ceasefire is due to take effect at 8 a.m. local time (12 a.m. EDT) on October 26, the US State Department and the governments of Azerbaijan and Armenia said in a joint statement on Sunday.
"Congratulations to Armenian Prime Minister Nikol Pashinyan and Azerbaijani President Ilham Aliyev, who just agreed to adhere to a ceasefire effective at midnight. Many lives will be saved," US President Donald Trump wrote on Twitter.
The announcement came after US Secretary of State Mike Pompeo held separate meetings with the foreign ministers of Armenia and Azerbaijan in Washington on Friday.
The Minsk Group said its co-chairs and the foreign ministers agreed to meet again in Geneva on October 29.
But the eruption of new fighting on Sunday and the collapse of two previous ceasefires brokered by Russia raised questions about the prospects for this fresh push to end the clashes in Nagorno-Karabakh, a part of Azerbaijan populated and controlled by ethnic Armenians.
But new fighting erupted between Azerbaijan and ethnic Armenian forces on Sunday as both sides blamed each other for blocking a peaceful settlement to the conflict.
Armenia has accused Azerbaijani forces of shelling civilian settlements. Baku denied killing civilians and said it was ready to implement a ceasefire, provided that Armenian forces withdrew from the battlefield.
The weekend's clashes in and around Nagorno-Karabakh came after US Secretary of State Mike Pompeo hosted the foreign ministers of both countries in a new peace push on Friday.
The collapse of two Russia-brokered ceasefires had already dimmed the prospect of a quick end to fighting that broke out on September 27 over Nagorno-Karabakh.
Azerbaijan said its positions had been attacked with small arms, mortars, tanks, mortars, and howitzers.
Armenian President Armen Sarkissian accused Baku of being "aggressively stubborn and destructive".
World powers want to prevent a wider war that draws in Turkey, which has voiced strong support for Azerbaijan, and Russia, which has a defence pact with Armenia.
Aliyev said it was "very hazardous" for Armenia to want Russian military support in the conflict and third parties should not get involved militarily.
Russian President Vladimir Putin has said he hoped that the United States would help Moscow broker a solution to the conflict.