Both sides in the long-running conflict over the breakaway Azerbaijani territory of Nagorno-Karabakh accused the other of launching fresh attacks despite a six-day-old, Russian-brokered cease-fire that has mostly failed to take hold.
Baku and Yerevan each claimed hard-fought gains in the fighting in and around the territory, which was mostly populated by around 150,000 ethnic Armenians before the flare-up started on September 27.
There are fears that the decades-old conflict could engulf the region in a conflagration involving Azerbaijan's biggest ally, Turkey, and Russia, which guarantees Armenia's security under the Collective Security Treaty Organization (CSTO).
U.S. Secretary of State Mike Pompeo on October 15 appeared to send a veiled message to Turkey suggesting it was inflaming a "dangerous" situation by arming and publicly backing Baku's actions.
"We now have the Turks, who have stepped in and provided resources to Azerbaijan, increasing the risk, increasing the firepower that’s taking place in this historic fight over this place called Nagorno-Karabakh, a small territory with about 150,000 people," Pompeo told an Atlanta radio station.
He called for "negotiation and peaceful discussions...and certainly not...third parties coming in to lend their firepower to what is already a powder keg of a situation."
Armenia has accused foe Turkey of encouraging Azerbaijan to try to militarily attack a problem that decades of internationally mediated talks have failed to resolve.
The Armenian Defense Ministry's Artsrun Hovhannisian said on October 16 that Azerbaijani forces had bombarded Nagorno-Karabakh from the north "with total disregard for the humanitarian truce."
The Azerbaijani Defense Ministry said a retreat by ethnic Armenian forces in the territory had left Baku's troops with an advantage along the Line of Contact that divides the warring sides.
Baku also accused Yerevan of a missile attack on an autonomous exclave of Azerbaijan called Nakhchivan, hitting an area near Orduba but causing no casualties.
Armenia denied it carried out any such attack.
Accusations and counteraccusations are difficult to corroborate in the conflict, which has simmered with occasional low-intensity skirmishes since a cease-fire -- but no peace agreement -- was signed between the two former Soviet republics in 1994.
Nagorno-Karabakh is internationally recognized as part of Azerbaijan, but is mostly populated by ethnic Armenians who are backed by Yerevan.
The territory's de facto leadership reported 29 more deaths on October 16 to increase its death toll from this chapter of fighting to 633.
The Azerbaijani government does not release military casualty figures but has said 47 civilians have died.
Armenian Foreign Minister Zohrab Mnatsakanyan reportedly spoke by phone with UN Secretary-General Antonio Guterres and requested that the global community "neutralize" Azerbaijani actions that endanger "the people of Nagorno-Karabakh."
Iran’s Foreign Ministry issued a warning to Armenia and Azerbaijan after it said 10 stray rockets from the conflict wounded one person on the Iranian side of the border.
Visiting Greek Foreign Minister Nikos Dendias said in Yerevan that "Turkey's meddling in the Karabakh conflict causes us concerns."
He said Yerevan and Athens -- both capitals of predominantly Christian countries -- "have a shared problem: Turkey." Ankara, he said, is "ignoring the EU's calls to respect international law."
Greece and Turkey are currently in a major spat over energy and maritime resources in the eastern Mediterranean.
Russia on October 16 downplayed military exercises begun by its navy in the Caspian Sea, not far from Baku, saying they posed no threat to neighbors.
The exercises -- involving six warships, seven aircraft, and more than 400 servicemen -- "do not pose any threat and do not impose restrictions on the economic activities of the Caspian littoral states," the Russian Defense Ministry said.