New shelling has taken place in Ukraine near the airport of Donetsk, after overnight attacks rocked the port city Mariupol.
The fresh attacks in Donetsk on Sunday raised concerns that an existing ceasefire would cease to hold.
Reports say the blasts could be heard in downtown Donetsk.
The violence came shortly after there was heavy shelling of Ukrainian government positions in Mariupol.
On September 4, Ukrainian government forces and pro-Russians signed a ceasefire agreement backed by Moscow. Both sides have accused one another of violating the ceasefire.
On Saturday, a leading member of the parliament established by the self-proclaimed Donetsk People’s Republic said that Ukrainian units had launched several missiles toward the pro-Russians’ positions in the east after the ceasefire took effect.
Prior to the ceasefire agreement, pro-Russian militants had been advancing on both Donetsk airport and Mariupol, which is a key city on the way to Crimea.
Ukraine’s mainly Russian-speaking regions in the east have been the scene of deadly clashes between pro-Russia protesters and the Ukrainian army since the government in Kiev launched military operations in mid-April in a bid to crush the protests.
Violence intensified in May after the two flashpoint regions of Donetsk and Lugansk held local referendums in which their residents voted overwhelmingly in favor of independence from Ukraine.