US warns of 'lethal' military intervention as Ukraine and Russia prepare for war

With Russia and Ukraine on the brink of an all-out war, the US has declared it will not yet send weapons to the strife-torn region.

It comes as a massive explosion rocked the Ukrainian city of Donetsk, so large it was initially feared to be a nuclear attack.

It was in fact a chemical company on the city outskirts, believed to be destroyed by rockets fired by Russian-backed separatists.

The rebels themselves have claimed the plant was destroyed by Ukrainian military fire, while officials also pointed to a fallen cigarette as causing the blast.

The deteriorating situation in Ukraine brought German Chancellor Angela Merkel to Washington for talks with US president Barack Obama.

Russian president Vladimir Putin isn't budging on his support for the breakaway movement and the US, Germany and other European nations are calling for a ceasefire.

This time, however, Mr Obama has warned if diplomacy fails it will lead to other, more brutal, solutions.

"What I've asked my team to do is look at all options,” Mr Obama said.

“What other means can we put in place to change Mr Putin's calculus and the possibility of lethal defensive weapons is one of those options that's being examined.

“But I haven't made a decision about that yet."

Ms Merkel had previously urged the US to refrain from providing Kiev weapons so as not to inflame the conflict.

Today she said if a new round of peace talks fails, other avenues will have to be considered.

The conflict has now killed more than 5300 people and displaced more than a million.

An indication of the ongoing trauma being inflicted on the innocent has been revealed in new vision to emerge from the war-torn city.

Locals were forced to dive for cover after rockets fired by the pro-Russian rebels landed close to a soup kitchen.

In the video, one woman speaks for many in the region as she speaks through her tears.

"Why is happening again?” she asks.

“When will all this end?"