Crimean ethnic Tatars protest on the roadside in the settlement of Kok-Asan with a banner reading “No war!” as Russian troops move toward Simferopol on Ukraine’s Crimean Peninsula.

March 8, 2014 Crimean ethnic Tatars protest on the roadside in the settlement of Kok-Asan with a banner reading “No war!” as Russian troops move toward Simferopol on Ukraine’s Crimean Peninsula. Denis Sinyakov/European Pressphoto Agency

Russian troops and pro-Russian militants take up positions around the Crimean Peninsula in Ukraine, surrounding government buildings and military installations.

Russian troops and pro-Russian militants take up positions around the Crimean Peninsula in Ukraine, surrounding government buildings and military installations.

Russian troops and pro-Russian militants take up positions around the Crimean Peninsula in Ukraine, surrounding government buildings and military installations.

— The head of Ukraine’s new pro-Western government will meet with President Obama this week, the White House announced Sunday, as a defiant Russia took further steps to consolidate its hold on the Crimean Peninsula.

The announcement of Wednesday’s meeting in Washington with Prime Minister Arseniy Yatsenyuk came as pro-Russian forces extended their reach in Crimea, surrounding a border post in the far west and blocking Ukrainian TV broadcasts to the heavily Russian-speaking region, which lies more than 400 miles southeast of the Ukrainian capital. There were reports of more troop movements into Crimea, with officials in Kiev estimating that 18,000 pro-Russian forces had fanned out across the region, which is about the size of Massachusetts.

A whirlwind of diplomacy continued Sunday — with Russian President Vladimir Putin speaking to German Chancellor Angela Merkel and British Prime Minister David Cameron — but there was no sign that Putin was willing to budge.

The Yatsenyuk visit was announced Sunday by Tony Blinken, Obama’s deputy national security adviser. “What we’ve seen is the president mobilizing the international community in support of Ukraine to isolate Russia for its actions in Ukraine, and to reassure our allies and partners,” Blinken said on NBC’s “Meet the Press.”

Geoffrey R. Pyatt, U.S. ambassador to Ukraine, said at a news conference in Kiev that Obama’s talks with Yatsenyuk would focus on the Crimea crisis as well as the dire economic situation in Ukraine. He reiterated that there is no “military solution” to the crisis and called on the Ukrainian military to continue to show restraint in the standoff with Russia.

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He said diplomatic efforts were continuing, insisting Washington and its European partners were in broad agreement on steps to push Russia toward direct talks with the new government in Kiev.

He added that teams from the U.S. Treasury, Department of Justice and FBI had landed in Kiev and were actively working with the Ukrainians to follow money trails and unravel the “kleptocracy” of former President Viktor Yanukovych’s deposed government.

Yanukovych plans to make a public statement Tuesday in the southern Russian city of Rostov-on-Don, Interfax said, quoting a source close to Yanukovych. The time and place were not specified. Yanukovych has mostly kept out of sight since fleeing Ukraine, although he gave a press conference in Rostov Feb. 28, when he said he would not ask Russia to send troops to Ukraine. A few days later Russian officials said he had written a letter the next day appealing for military help.

Raising concerns of unrest beyond Crimea, local news media and Russia’s Interfax news agency reported that hundreds of activists brandishing Russian flags had broken into a government building in the eastern Ukrainian city of Luhansk. They reportedly forced the mayor to write a resignation letter and raised the Russian flag over the building. The incursion occurred two days after a similar protest in the eastern city of Donetsk was put down by authorities loyal to the new government in Kiev.

Russia’s foreign ministry on Monday said it was “outraged by the chaos which is currently ruling in eastern regions of Ukraine,” and blamed both right-wing militants and the “connivance of the new authorities,” according to Interfax. The ministry alleged that “well-equipped people in masks and with firearms opened fire at peaceful protestors” in the eastern city of Kharkiv on Saturday, causing injuries.

But Crimea remained the core of concern. According to a spokeswoman for the Ukrainian coast guard, most Ukrainian broadcasts in the region were jammed beginning mid-afternoon Sunday. The only Ukrainian TV programming that could be seen by a reporter in Sevastopol was on two channels, one showing movies and the other soccer.

On Sunday, Sevastopol — home of Russia’s Black Sea Fleet — was awash in Russian flags as the rest of Ukraine was celebrating the 200th birthday of national hero and poet Taras Shevchenko. Matrons walking down the street in woolen coats and sensible shoes had Russian flag ribbons tied to the straps of their purses. Children skated through squares wearing armbands with the tricolor stripes of the Russian flag.

Ukrainian border guards say a plane came under fire while flying near the border with Russian-occupied Crimea. Russian forces are tightening their grip on the peninsula. (Reuters)

Some of those who tried to show their Ukrainian pride paid a price. Several people at a pro-Ukrainian rally were beaten up by pro-Russian activists, said Dima Belotserkovets, a pro-Ukrainian activist. He said he and others were kicked and punched until police eventually came to their rescue. Ten pro-Ukrainian activists were detained but later released, he said. At least one other was still in the hospital, Belotserkovets said, and one was unaccounted for.

Putin defends referendum

Russia held out a financial carrot to Crimea, offering 40 billion rubles ($1.1 billion) in support if the peninsula voted in favor of joining Russia in a March 16 referendum. That vote was called by pro-Russian lawmakers who seized control of Crimea’s parliament on Feb. 27.

Sergei Aksyonov, the self-declared provincial leader in Crimea, told Russia’s RIA news service that if the territory becomes part of Russia, his government would encourage the use of two languages -- Russian and Crimean Tatar – but not Ukrainian, RIA reported on Monday.

In a phone call with Putin, Merkel called the planned referendum “illegal” and urged Putin to de-escalate the situation, according to a German government spokesman. Blinken said Sunday that if the vote favors annexing Crimea to Russia, “we won’t recognize it, and most of the world won’t either.”

Putin also spoke with Cameron, who continued a push for the Russian leader to support a contact group that could arrange direct talks between him and the new government in Kiev, according to a spokeswoman at the British prime minister’s office.

But the Kremlin’s news service said Putin stressed that “the steps being taken by the legitimate Crimean authorities are based on international law and aim to protect the legitimate interests of the population of the Crimea.”

The Chinese government signaled Monday that it will continue to stay out of the crisis, with President Xi Jinping telling President Obama in a phone call that it is “very important for all parties concerned to remain calm and exercise restraint,” according to the state-run Xinhua news service.

There were no reports of shots fired when Russian forces encircled the Chernomorskoye border post in western Crimea, but about 30 Ukrainian personnel were trapped inside, according to reports from the Reuters news agency and Ukrainian television. It was the 11th Ukrainian base to be surrounded by Russian forces since they moved into the region Feb. 28.

Tension at military bases

On Sunday, Ukrainian military bases around Sevastopol were tense but largely quiet, with commanders saying that they were trying to avoid responding to provocations.

At one isolated base a half-hour outside Sevastopol, a sign taped to the gate read “Thank you for staying faithful to your oath.” Outside the gate, a half-dozen men in uniforms — part of the pro-Russian “self-defense forces” — milled around.

“They say they are here to defend us from ‘terrorist attacks,’ ” said Col. Andrei Ivanchenko, the Ukrainian base commander, using his fingers to draw air quotes around the words. “They don’t talk to us. But they are peaceful.”

Ivanchenko said the self-defense units report to a commander in the Russian military, a colonel who had come to the base four days earlier and told the Ukrainians to disarm. Ivanchenko said Russian troops stayed outside the facility, with snipers posted on nearby rooftops.

He said the base had been receiving food and calls of support from civilians. Pointing to a Ukrainian flag flying on a pole at the base entrance, he said morale among those inside was “as high as that banner.”

No Russian or self-defense troops were visible at a nearby Ukrainian air force base that was stormed Friday night by Russian troops. But Lt. Col. Andrei ­Aladashvili, the base commander, said the installation was under the constant observation of Russians stationed on nearby rooftops and in apartment buildings.

About 50 people were inside the base, he said, half of them women. All the weapons in the facility had been removed and sent to an arsenal, he said, to avoid any incident.

“Our main task is not to use our weapons, not to have any victims,” he said. “We must not react to any provocation. That is the most important thing.”

Aladashvili described a harrowing attack on the base Friday night, when a Russian military truck tried to ram through the front gate about 7:30 p.m. and Russian soldiers scrambled over the low walls surrounding the facility. The Ukrain­ian troops on the base lined up just inside the gate, he said, forming a human shield to defend their facility. The Russian soldiers threatened to shoot them in the backs if they did not move, Aladashvili said.

The standoff continued for five hours while Russian and Ukrainian commanders negotiated over the phone, and, eventually, the Russians left at 12:30 a.m. Saturday, Aladashvili said.

Morello reported from Sevastopol. Isabel Gorst in Moscow and Philip Rucker in Washington contributed to this report.