Signs have emerged pointing to a major offensive in eastern Ukraine by rebels fighting to break off from the rest of the country.

An artillery shell or mortar struck a public transport stop in the rebel-controlled city of Donetsk in eastern Ukraine, killing at least 11 civilians in an incident which both sides blamed on the other.

Pro-Russian rebels in eastern Ukraine have claimed to have seized control of the Donetsk airport after days of intense fighting.

An attack on a passenger bus in eastern Ukraine has killed 11 people, likely dealing the final blow to hopes that a short-lived and shaky ceasefire could take hold.

Ukraine's President Petro Poroshenko has ordered army reinforcements to key southern and eastern cities, in case of a new rebel offensive.

The leader of separatist rebels in eastern Ukraine has been officially sworn in after an election that was roundly condemned by the West as destabilising.

Residents of separatist-controlled regions in eastern Ukraine have been voting to elect legislators and executives in polls that have been staunchly denounced by the international community.

Rebels in eastern Ukraine appear to be successfully closing in on the government-held airport in Donetsk, a strategic victory for the pro-Russian separatists that further undermines a shaky ceasefire in the region.

Ukraine, Russia and the Kremlin-backed separatists signed a ceasefire deal after five months of bloodshed, and Europe prepared additional sanctions on Moscow.

Army troops have penetrated deep inside a rebel-controlled city in eastern Ukraine in what could prove a breakthrough development in the four-month-long conflict, the Ukrainian government said today.

Separatists have shot down a Ukrainian fighter plane amid fighting between pro-Russian rebels and Ukrainian government forces in the eastern part of the country.