Ukrainian and separatist forces clashed Wednesday around the Sea of Azov port town of Novoazovsk, on the southern end of separatist territory just eight miles from the Russian border. NATO, the United States and Ukraine have all accused Russia of leading an offensive in eastern Ukraine that has opened up a new, troubling front in the conflict. 

The offensive includes tanks, artillery and infantry units, according to the New York Times. The Times report describes some weary Ukrainian soldiers choosing not to fight and instead fleeing artillery barrages for safer territory to the west. The Ukrainian military said it was still in control of Novoazovsk in the early evening, but the mayor said pro-Russian troops had moved into his town of 12,000. 

Swedish Foreign Minister Carl Bildt, among others, accused Russia of direct intervention: 

Novoazovsk is along the coast of the Sea of Azov (an arm of the Black sea), on a key road leading to Mariupol, a city Ukrainain forces recaptured in June. That road connects Russia with the Crimean Peninsula, which Russia annexed in March. Russia denies it is supporting the offensive there, but local reports claim the attack came from the direction of the border, from an area only reachable via Russia or the territory held by Ukrainian forces.

“These incursions indicate a Russian-directed counteroffensive is likely underway in Donetsk and Luhansk,” U.S. State Department spokeswoman Jen Psaki said Wednesday.

The offensive comes just a day after Ukrainian President Petro Poroshenko met with Russian President Vladimir Putin in Belarus to discuss a solution to the crisis. Ten Russian paratroopers were captured by Ukrainian forces in Ukrainian territory on Tuesday, just before the summit meeting, further complicating those talks. Russia’s Defense Ministry said those troops were in Ukraine by accident.

Poroshenko said early Wednesday that a “road map” to peace would be planned immediately, but he has not yet spoken out about the fighting near Novoazovsk, which could derail that plan. More than 2,500 people have been killed in the conflict, including nearly 300 civilian passengers aboard Malaysian Airlines Flight MH17 when it was shot down over separatist-held territory on July 17.