NOVOAZOVSK, Ukraine (AP) — Separatist rebels shelled a town in southeastern Ukraine on Wednesday, raising fears they are launching a counter-offensive on government-held parts of the region, one day after the leaders of Ukraine and Russia met to discuss the escalating crisis.

In response to outgoing fire early Wednesday, rebel forces lobbed at least 10 shells at the government-held town of Novoazovsk. Plumes of black smoke rose above the town, which was also hit repeatedly by shelling Tuesday, injuring four people in a hospital, mayor Oleg Sidorkin said.

Novoazovsk lies on the Azov Sea on the road that runs from Russia to the major Ukrainian port of Mariupol and west to Crimea, raising fears the separatists are seeking to create a land link between Russia and Crimea, which Russia annexed in March.

On Tuesday, Russian President Vladimir Putin and his Ukrainian counterpart, Petro Poroshenko, met in the Belarusian capital of Minsk for their first ever one-on-one meeting, which lasted over two hours. But there was no indication of a swift resolution to the fighting that has dragged on since April and claimed at least 2,000 civilian lives.

Poroshenko called the talks "overall positive" and said Putin had accepted the principles of his peace plan, which includes an amnesty for those in the east not accused of serious crimes and calls for some decentralization of power to the region.

Putin, however, insisted that only Kiev could secure a cease-fire deal with the pro-Moscow separatists, saying the conflict was "Ukraine's business."

Russia "can only help to create an atmosphere of trust for this important and necessary process," Putin said. "We in Russia cannot talk about any conditions for the cease-fire, about any agreements between Kiev, Donetsk, Luhansk," the two rebel regions.

Kiev and the West have repeatedly accused Russia of supplying arms and expertise to the rebels in eastern Ukraine, something Moscow denies.

But Associated Press journalists on the border have seen the rebels with a wide range of unmarked military equipment — including tanks, Buk missile launchers and armored personnel carriers — and have run into many Russians among the rebel fighters. Ukraine also captured 10 soldiers from a Russian paratrooper division Monday around Amvrosiivka, a town near the Russian border.

Ukraine wants the rebels to hand back the territory they have captured in eastern Ukraine, while Putin wants to retain some sort of leverage over the mostly Russian-speaking region so Ukraine does not join NATO or the European Union.

Putin has so far ignored requests from the rebels to be annexed by Russia.