By David Brennan, Newsweek–

President Donald Trump has said his administration is looking “very strongly” at an outbreak of violence between Armenia and Azerbaijan over the disputed Nagorno-Karabakh region, which has left dozens dead and raised fears of a broader war between the Caucasus neighbors.

President Donald Trump has said his administration is looking “very strongly” at an outbreak of violence between Armenia and Azerbaijan over the disputed Nagorno-Karabakh region, which has left dozens dead and raised fears of a broader war between the Caucasus neighbors.

The two nations went to war between 1988–94 over the region, which broke away from Azerbaijan after the collapse of the Soviet Union. Since then there have been sporadic border clashes. This weekend’s violence is the most significant since 2016, when hundreds of troops on both sides were killed during a spate of border fighting.

Heavy artillery, helicopter gunships and armed drones were all deployed over the weekend, with reports of civilian casualties caused by shelling.

Both sides are claiming self-defense in the face of cross-border aggression, and Armenia has implemented martial law and announced full military mobilization. Azerbaijan on Monday announced it had begun partial mobilization of its military.

Asked about the fighting on Sunday, Trump said: “We’re looking at it very strongly. It just happened. And I know about it. I learned about it today and yesterday. And we’re looking at it very strongly. We have a lot of good relationships in that area. We’ll see if we can stop it.”

The president did not elaborate on how the U.S. would try and stop the violence. The State Department released a separate statement condemning the fighting and calling on both sides to refrain from actions or rhetoric that could escalate the situation.

Democratic presidential candidate and former Vice President Joe Biden meanwhile called on Trump to push for more observers along the ceasefire line separating the combatants, and to put pressure on Russia “to stop cynically providing arms to both sides.”

Democratic New Jersey Sen. Bob Menendez—the ranking member of the Senate Foreign Relations Committee—blamed Azerbaijan for the outbreak of fighting, and called on the administration to suspend security assistance to the country.

The U.S. has supported both nations with security assistance, but under Trump has significantly expanded its financial support for Azerbaijan as part of its effort to isolate and contain neighboring Iran.

U.S military aid to Azerbaijan jumped from around $3 million in 2016-17 to some $100 million in 2018-19. Armenia received $4.2 million in U.S. security assistance in the 2018 financial year.

The foreign ministers of Turkey—which backs the Azeri government—and Russia—traditionally seen as favoring the Armenians—spoke on Sunday and discussed the importance of a ceasefire, according to Russia’s Tass state news agency.

“The need for an early ceasefire and stabilization of the situation on the contact line was emphasized” a statement from Russia’s foreign ministry said. “Condolences were expressed to the families and friends of the victims.”

But Turkish President Recep Tayyip Erdogan was less diplomatic, expressing his support for the Azeris in their “battle against invasion and cruelty.”