Pro-Russian rebels in eastern Ukraine were today continuing an offensive to take the government-held airport in Donetsk, it has been reported.

Insurgents have tried to remove government forces from the site as fighting for the key hub has raged on for months.

Rebel forces today continued a push to take the site, which started on Wednesday, the BBC has quoted the Ukraine military as saying.

At least nine people were killed in the crossfire yesterday as fighting took place in residential areas near the airport.

Government forces have used the airport to shell insurgent positions in Donetsk, the largest rebel-held city.

Despite a ceasefire having been in place since 5 September, civilian and military casualties have continued to rise.

As fighting continued yesterday, one shell killed at least three people when it exploded in a school courtyard.

Donetsk city council said a teacher and two parents were killed at the school, while 70 schoolchildren had been at the site at the time.

It also said six people were killed and several wounded when another shell hit a nearby bus stop.

The United Nations has strongly condemned the shelling of the school.

Stephane Dujarric, spokesman for the UN Secretary-General, said the "targeting of schools is unacceptable in any circumstances."

"All parties should redouble their efforts to find a diplomatic solution," he added.

Additional reporting by Associated Press