Baseball star David 'Big Papi' Ortiz met President Obama today and, naturally, asked for a selfie.
Barack Obama warned Russia that the West will be forced to apply a cost to Moscow if it fails to change course in its dispute with Ukraine.
The Cold War has returned with a vengeance, judging by the mood in Washington with talk of extensive sanctions against Russia.
Economic sanctions will remain the primary weapon as the US and its European allies tackle the Ukraine crisis, Obama administration officials said.
President Barack Obama travels across the Atlantic next week and will seek a cohesive stance from European leaders unnerved by Russia's annexation of Crimea but cautious about the economic punishment the US says it is willing to unleash.
"Our interest is not in seeing this situation escalate and devolve into hot conflict," National Security Adviser Susan Rice said.
"Our interest is in a diplomatic resolution, de-escalation and, obviously, economic support for Ukraine, and to the extent that it continues to be necessary, further cost imposed on Russia for its actions."
President Barack Obama said the US will not get involved in a "military excursion" in Ukraine, in an interview with KNSD TV.
President Obama has come out to condone Russia's actions in Crimea by imposing sanctions on key individuals.
The US has said it is imposing sanctions on 11 people. Those include Russian government officials - including aides to Russian President Putin, Vladislov Surkov and Sergei Glazyev, Crimea-based separatist leader Vladimir Konstantinov and ousted Ukrainan President Viktor Yanukovych.
He said: "The future of Ukraine must be decided by the people of Ukraine. Ukraine's sovereignty and territorial integrity must be respected." He continued by saying the Crimean referendum won't be recognized by the international community.
"We will calculate a response if Russia chooses to escalate or de-escalate the situation. We are standing firm in our unwavering support for Ukraine."
President Obama has told Vladimir Putin today's referendum in Crimea "would never be recognised" by the US or the rest of the international community, the White House has said.
US President Barack Obama has warned Russia that the West will be forced to apply a cost to Moscow if it fails to change course in the ongoing Ukraine crisis.
Obama held face-to-face talks with the new Ukrainian Prime Minister Arseniy Yatsenyuk in the White House and told reporters, "We will stand with Ukraine."
Yatsenyuk said Ukraine is ready for talks and vowed, "We will never surrender" to Russia.
US President Barack Obama will meet with Ukrainian Prime Minister Arseny Yatseniuk at the White House on Wednesday.
The White House called the meeting, which comes just days before a referendum on secession by Crimea, a "show of support for Ukrainian sovereignty."
The leaders are set to talk about "how to find a peaceful resolution to Russia's ongoing military intervention in Crimea that would respect Ukrainian sovereignty and territorial integrity," the White House said.
President Obama made a series of phone calls on Saturday to world leaders about the ongoing crisis in Ukraine, including Prime Minister David Cameron, French President Francois Hollande, and Italian Prime Minister Matteo Renzi, the White House said.
He also held a conference call about the situation with the presidents of Lithuania, Latvia and Estonia, White House spokesman Josh Earnest said in a statement.
President Barack Obama has urged Russian President Vladimir Putin to accept the terms of a potential diplomatic solution to the Ukraine crisis.
In their second phone conversation in the past six days, Obama outlined the terms of a diplomatic "off-ramp" that US officials are promoting.
Under terms of the deal, Russia would pull back troops to bases in Crimea, allow international monitors in to ensure the rights of ethnic Russians are respected and consent to direct talks with Ukraine officials.
"President Obama indicated that there is a way to resolve the situation diplomatically," the White House said in a statement.
US President Barack Obama spoke to Russian President Vladimir Putin for an hour to discuss the situation in Ukraine.
"President Obama emphasised that Russia’s actions are in violation of Ukraine’s sovereignty and territorial integrity, which has led us to take several steps in response, in coordination with our European partners," the White House said.