US President Barack Obama has said that the America has done everything possible to seek a diplomatic solution to Ukraine crisis, short of going into war to deter Russia.
"With respect to Ukraine, I think we have done everything that we can to support the Ukrainian government and to deter Russia from moving further into Ukraine," Obama told reporters at White House when asked if the US could have done more on Ukraine.
"But short of going to war, there are going to be some constraints in terms of what we can do if (Vladimir) Putin and Russia are ignoring what should be their long-term interests," he said.
"Right now, what we've done is impose sufficient costs on Russia that President Putin should want to resolve this diplomatically, get these sanctions lifted, get their economy growing again, and have good relations with Ukraine," he said.
Meanwhile, the Pentagon has alleged that Russia continues to support the Ukrainian separatists.
"The Russian government continues to support the separatists in eastern Ukraine. So taken as a whole, their activities continue to destabilise the region," Pentagon Press Secretary Rear Admiral John Kirby said.
"On what we see from Russia, I would just say broadly we continue to see them reinforce the troops that they have in the southeast border there with Ukraine. They continue to be reinforced. They continue to represent what we consider a combined arms capability, very capable, very ready forces.
"They're close to the border, within 50 kilometres of the border. So closer than what we saw back in the spring," Kirby told Pentagon reporters at a news conference.
The US assistance to Ukrainian Government, he said, remains restricted to non-lethal aid.
"The focus of our assistance remains on non-lethal. We continue to review requests for military assistance from the government of Ukraine through an interagency process. No decisions have been made yet to move beyond non-lethal," he said in response to a question.
Referring to the previous statements of the US President, the Pentagon spokesperson said there would not be a military solution to the situation in Ukraine.
"We also need to be mindful that we don't take actions that make it worse or make even less secure for the Ukrainian people," he added.