Ukrainian authorities and pro-Russian separatists accused each other on Thursday of carrying out fresh artillery attacks on frontline residential areas in eastern Ukraine, resulting in civilian casualties on both sides.
The reports follow a short lull in fighting in the wake of the deadliest clashes in recent months that have brought global attention back to the conflict. NATO and the EU have called on Russia to use its influence with rebels to stop the violence.
The head of the Ukraine-controlled Donetsk regional administration, Pavlo Zhebrivsky, said a humanitarian aid point in the government-held industrial town of Avdiyivka had been hit by mortars late on Thursday.
"According to preliminary figures, one person has been killed and one wounded in the attack. Shelling continues," he said on Facebook, blaming Russia-backed rebels.
In a separate post, Zhebrivsky said one civilian was killed by shelling in another part of the industrial town that has been the focal point of the recent flare-up in hostilities.
Damage from the escalation has cut power and water supplies to thousands of residents on both sides of the front line at a time of freezing winter temperatures, prompting warnings of a potential humanitarian crisis from aid agencies.
Separatist officials said around 10 civilians had been wounded as a result of fresh shelling by Ukrainian forces, also on Thursday evening, separatist website DAN reported.
None of the casualty reports have been independently verified.
Earlier the International Committee of the Red Cross in Ukraine called for all sides to hold fire to allow the emergency repair work to be carried out on damaged utilities infrastructure.
In a statement, the head of ICRC in Ukraine, Alain Aeschlimann, warned of "potentially tremendous humanitarian consequences" if the situation for civilians living near the eastern front line does not improve.
A Reuters witness in Avdiyivka said the intermittent boom of artillery fire could be heard in the distance throughout the day.
A February 2015 'Minsk' peace agreement locked the two sides in a stalemate which has been broken periodically by surges in fighting that Kiev and the Kremlin accuse each other of instigating.
Thirteen Ukrainian servicemen have been killed and around 30 wounded since Sunday, according to the military's press service in Kiev. Separatists have also reported casualties among their fighters but not provided an exact toll on a regular basis.
The clashes come as Kiev seeks to persuade the United States and the European Union of the need to maintain economic sanctions against Russia linked to its involvement in the conflict and annexation of Crimea.
Moscow denies accusations from Kiev and NATO that it supports the separatists with troops and weapons.
This is the first significant escalation of violence in Ukraine since the inauguration of President Donald Trump, whose call for better relations with Moscow has alarmed Kiev with the conflict unresolved.
On Thursday, Russian President Vladimir Putin accused Kiev of provoking the flare-up as a ploy to win the support of the Trump administration.
But US Senator John McCain said Russia had instigated the violence to test Trump, and he urged the president to give Ukraine the lethal aid it needs to defend against the attacks.
Fighting between pro-Russian separatists and government forces first broke out in April 2014 after a pro-European uprising in Kiev ousted a Moscow-backed president. Close to 10,000 have since been killed.
