An injured man arrives on a stretcher at hospital after a shelling in Donetsk, eastern Ukraine on October 1, 2014
Donetsk (Ukraine) (AFP) - Ukraine's largest rebel-controlled city of Donetsk was shaken by violence on Wednesday as 10 people, including parents and teachers, were killed, the highest toll since a tenuous ceasefire was agreed.
Terrified children, arriving for the first day of school, were forced to shelter in the basement as the shelling yielded the highest single civilian toll since the ceasefire was struck between Kiev and pro-Russian separatists last month.
Clashes have raged for days at several flashpoints around the region, with both sides blaming the other for violating the agreement that commits them to withdrawing weapons and establishing a buffer zone.
The United States has decried the violence while the European Union decided Tuesday to keep Russian sanctions in place, maintaining pressure on Moscow in the worst East-West standoff since the Cold War.
German Chancellor Angela Merkel, during a telephone call with President Vladimir Putin Wednesday, stressed Moscow's "responsibility" to act as a moderating influence over the pro-Russian separatists in Ukraine.
She "insisted on Russia's responsibility to exercise a moderating influence on the pro-Russian separatists," a German government spokesman said.
The pro-Kiev regional government of Donetsk based in the government-controlled city of Mariupol accused pro-Russian separatists from the "Donetsk People's Republic" of shelling the school.
Four adults were killed, it said in a statement. Six more died when another shell struck a minibus at a bus stop about 500 metres from the school.
"I was going to open the doors to let passengers in and out when it happened," the driver of the vehicle, Mikhail Drobotun, told AFP as he sat in a local clinic where dozens of the injured were being treated.
"I was injured in the leg, someone pulled me out," he said. "It hit the back of the bus."
The strike happened right after the school's 70 pupils lined up for an assembly to mark the first day of class -- held nationally on September 1 but pushed back by rebel authorities because of the conflict.
Official rebel website DNR Today blamed the attack on Ukrainian artillery, claiming rebels do not possess the relevant weaponry and saying two security guards at the school were among the victims.
Russian media and separatist websites showed footage of rebels launching attacks from positions in apartment buildings near the airport.
Amnesty International in a statement urged Ukrainian and rebel forces to "immediately end indiscriminate attacks in residential areas", adding that both sides shared the blame for endangering civilians.
- EU, Ukraine to discuss Russian 'gas war' -
Crisis-hit Ukraine and the European Union will try on Thursday to forge a joint stance ahead of crunch talks with Russia in the latest gas war with its westward-leaning neighbour.
The meeting of Ukraine and EU energy officials in Brussels became even more critical after EU member Slovakia reported a 50-percent drop in Russian supplies following its decision to divert imports to Ukraine to help ease its spreading fuel shortage.
Europe's top energy envoy will then try on Friday to convince both the Kiev and Moscow gas chiefs, during talks in Berlin, to strike a compromise before winter forces Ukraine to consider tapping into the Russian gas bound for Europe.
Russia cut its deliveries to Ukraine in mid-June after a pro-Western government took power, saying that Kiev had not been paying its bills on time.
Jens Stoltenberg, the new NATO chief who took office Wednesday, argued in his opening remarks that "Russia maintains its ability to destabilise Ukraine" and "remains in breach of international law".
A delegation of about 70 Russian officers has however been working with Kiev since the weekend as part of a monitoring group.
Military spokesman Andriy Lysenko said that monitors, comprised of representatives from the Russian and Ukrainian militaries as well as the Organisation for the Security and Cooperation in Europe, have begun to patrol regions most frequently hit by ceasefire violations.
- Election season kicks off -
While the latest deaths lifted the toll to 68 since the truce deal was struck on September 5, Ukraine on Wednesday officially started its election season ahead of snap parliamentary polls on October 26.
Ukraine's central election commission said that nearly 3,500 candidates had registered for the election called last month by President Petro Poroshenko, more than a third of them as independents.
Poroshenko is also keen on holding the vote in the separatist regions, he stressed to Austrian Chancellor Werner Faymann who was in Kiev on a one-day visit.
However the separatists of Lugansk and Donetsk have vowed to boycott the polls and hold a vote of their own on November 2 for the regional leaders and legislative bodies.