Ethnic Armenians in Azerbaijan's breakaway region of Nagorno-Karabakh agreed to a Russian proposal for a ceasefire on Wednesday, 24 hours after Azerbaijan began an offensive to take control of the enclave that killed dozens and injured hundreds.
The separatist Armenian forces in Karabakh said Azerbaijan had broken through their lines and seized a number of strategic road junctions.
The self-styled "Republic of Artsakh" said that in such circumstances, it had no choice but to cease hostilities from 1:00 pm local time on Wednesday.
"The authorities of the Republic of Artsakh accept the proposal of the command of the Russian peacekeeping contingent to cease fire," it said.
"With the mediation of the command of the Russian peacekeeping contingent stationed in Nagorno-Karabakh, an agreement was reached on the complete cessation of hostilities from 13:00 on September 20."
Azerbaijan began its operation against Nagorno-Karabakh on Tuesday after some of its troops were killed in what Baku said were attacks from the mountainous region, which Azerbaijan had blockaded for nine months.
Nagorno-Karabakh is recognised internationally as part of Azerbaijan.
The Strait of Hormuz remains open to all shipping except vessels linked to "Iran's enemies", Iran's representative to the UN maritime agency was quoted as saying in Iranian media reports published on Sunday.
The Gulf Cooperation Council (GCC) has renewed its condemnation of continued Iranian attacks on member states, including the targeting of infrastructure and oil facilities, in flagrant violation of international law and a direct threat to regional security, stability and the safety of global energy supplies.
The Qatar Ministry of Interior has confirmed six people died during a helicopter crash into "regional waters" on Sunday - with search and rescue teams still searching for the body of the seventh and final crew member.
Japan could consider deploying its military for minesweeping in the Strait of Hormuz, a vital artery for global oil supplies, if a ceasefire is reached in the U.S.-Israeli war on Iran, Foreign Minister Toshimitsu Motegi said on Sunday.