Russian soldiers on Friday reportedly stormed a Ukranian military base 5 kilometers from the Ukranian city of Sevastopol, located on the Black Sea coast of the Crimean peninsula. The standoff was resolved without a shot being fired, a witness said.

According to early reports, members of a pro-Russia militia used a truck to break through the gate of the base. The truck got stuck at the gate, and Russian soldiers climbed over it. Some 70 Ukrainian troops were said to still be holding out in the bunkers. The militia troops who broke through the perimeter demanded the Ukrainian soldiers surrender.

The two sides were reportedly in the middle of negotiating the Ukrainian soldiers' terms of surrender, when a pro-Russian Cossack militia started assaulting journalists who were reporting from the area. At least one journalist was said to need medical treatment.

Crimea's pro-Russia premier, Sergei Aksyonov, was asked about the incident during a political chat show shown live on Ukrainian television and said all was calm at the military post.

Referring to the armed men as "self-defense units," he indicated the standoff was over, adding: "Now the self-defense units are surrounded by journalists. There are no attempts to attack."

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A Ukrainian military official, Vladislav Seleznyov, told Reuters by telephone that the armed men took over the base without any shooting and that no one was hurt. Another Ukrainian official told Reuters at the post that he was now mediating between the Ukrainian forces and the armed group inside, and that no arms had been seized.

Russia now has 30,000 troops in Ukraine's Crimea region, according to Ukrainian border guards, nearly twice the previous figure given by the government in Kiev.

Meanwhile, Russia said on Friday that any American sanctions imposed against Moscow over the Ukraine crisis would boomerang back on the United States and urged Washington not to damage bilateral ties.

In a phone conversation with U.S. Secretary of State John Kerry, Foreign Minister Sergei Lavrov "warned against hasty and reckless steps capable of causing harm to Russian-American relations, particularly ... sanctions, which would inevitably hit the United States like a boomerang," the Foreign Ministry said.

Canada, home to more than 1 million people of Ukrainian descent, imposed its own travel bans Friday on people threatening Ukraine's territorial integrity. Canadian Prime Minister Stephen Harper said the ban was to protest Russian President Vladimir Putin's "illegal military occupation" of Crimea.

Earlier Friday, President Vladimir Putin's spokesman Dimitry Peskov lashed out at the West and defended Russia's actions in Ukraine, but said he hoped a new Cold War would not break out despite "extremely deep disagreements."

The remarks, broadcast on one main state channel while another showed the Paralympic Games opening ceremony, appeared to be part of an effort by Putin to avoid a major confrontation with the West while giving no ground in the dispute over Ukraine.

Peskov said, "Extremely deep disagreements of a conceptual nature between Russia and the European Union and the United States have already been registered."

But he added: "There still remains hope ... that some points of agreement can be found as a result of dialogue - which our partners, thank God, have not yet rejected."

Peskov said calls for talks between Russia and Ukraine with the West as a mediator "make us smile." He said Western countries had failed to follow through on a February 21 peace deal between Ukraine's Viktor Yanukovich and his foes, and that this had cost them their credibility.

Peskov said the Kremlin was not behind moves by leaders in Ukraine's Crimea region to secede from Ukraine and join Russia. But Moscow was concerned there would be ethnic persecution if those behind what he called the "coup" that brought down Yanukovich were to reach Crimea or eastern Ukraine.

Ukraine seeks united Western front

Former boxer Vitali Klitschko and magnate Petro Poroshenko, both potential Ukrainian presidential contenders urged the U.S. and European Union on Friday to stick to a single, tough stance against Russia over its military incursion into Crimea.

While Washington is imposing sanctions and strongly criticizing Moscow, the EU has taken softer measures. Some European countries are wary of antagonizing Russia, a major energy supplier and trade partner, and anything that might lead to war on this continent.

Poroshenko told reporters in Paris that Ukraine wants the EU and U.S. "to speak in one voice and be on the same wavelength."

Klitschko, a leader of the protest movement that sent Ukraine's president fleeing last month, said, "we need a joint position by all EU countries and the United States."

Klitschko told The Associated Press that "of course" he is afraid of Russian aggression, but said the standoff over Crimea shouldn't be solved "on a military level."

"We must do everything so that not a single drop of blood is spilled," he said at Le Bourget Airport.

President Francois Hollande maintained a cautious tone in meetings with the two men Friday. While criticizing Crimean lawmakers' efforts to break away from Ukraine and join Russia, Hollande said he wants to "leave open the path of dialogue so that Russia can seize it whenever it decides to do so."

EU leaders imposed limited sanctions on Russia on Thursday, while President Barack Obama slapped visa restrictions on opponents of Ukraine's new government and authorized wider financial penalties.

The cautious EU position reflects divisions within the continent, but also the nature of a union created to prevent war and ease trade after centuries of conflict. The bloc reaches all of its decisions by painstaking consensus.

"America is one country and it can take steps, it does things in a slightly different way from the European Union. The European Union is 28 sovereign countries who have to agree together," British Prime Minister David Cameron said after an EU summit Thursday night.