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A senior U.S. State Department official reportedly is denying claims from Russia’s foreign minister that Moscow and Western powers favor a European Union-brokered deal to resolve Ukraine’s political crisis.

The official, speaking to Reuters, said there were “no agreements” in a Wednesday meeting between Sergey Lavrov and Secretary of State John Kerry, and there never will be without direct Ukrainian government involvement and absolute buy-in.”

In other developments:

• Around 5,000 supporters of Ukraine rallied in Kiev’s central square, chanting anti-Russia slogans while police kept them away from around 1,000 pro-Moscow protesters nearby, Reuters reports.

• Around 100 protesters waving Russian flags marched on a building used by international observers in Ukraine’s Crimea region, a Reuters photographer reports.

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    • Deputy U.N. Secretary General Jan Eliasson is denying a report that a U.N. representative was kidnapped and held by armed men in Crimea, saying he was only threatened.

    • Hundreds of demonstrators waving Russian flags and chanting "Russia! Russia!" have stormed a government building in Donetsk in eastern Ukraine.

    • The European Union is preparing to freeze the financial assets in Europe of 18 people held responsible of misusing Ukrainian state funds.

    After meeting with Lavrov and other foreign ministers in Paris on the sidelines of a long-planned conference on Syrian refugees, Kerry said Ukraine, Russia and Western powers “agree to continue intense discussions” on the crisis in the days ahead.

    “We cannot, and will not allow the integrity and sovereignty of the country of Ukraine to be violated and for those violations to go unanswered,” Kerry said.

    Lavrov was quoted by the Interfax news agency as saying that Western powers agreed that both sides in Ukraine should stick to the Feb. 21 deal, according to Reuters.

    Under the EU-mediated plan, protest leaders and former Ukrainian president Viktor Yanukovych agreed to form a new government and hold early elections.

    The deal was struck before Yanukovych fled Kiev. In it, both sides agreed to restore Ukraine’s 2004 constitution and reduce the president’s powers, the BBC reports. It was signed by Yanukovych, opposition leaders and three EU foreign ministers, but not by a Russian official that was present.

    Prior to Wednesday’s meeting, Kerry had a “brief pull aside discussion” with Lavrov, where he “urged direct talks between Russia and Ukraine,” a senior State Department official told Fox News.

    Diplomats told Reuters that Lavrov left the talks without having met his Ukrainian counterpart. Kerry said he expects to meet with Lavrov again on Thursday in Rome.

    Earlier in the day, Kerry met with foreign ministers from Britain and Ukraine at the residence of the U.S. ambassador to Paris, but Russia did not attend, according to The Wall Street Journal.

    On Tuesday, Russian President Vladimir Putin claimed that none of Russia’s forces have moved into the Crimean Peninsula, drawing a stunned reaction from Kerry.

    Lavrov reiterated Putin’s claims on Wednesday. Asked if Russia could order the troops in the Crimea region back to their bases, Lavrov told a reporter in Madrid: “If you mean the self-defense units created by the inhabitants of Crimea, we give them no orders, they take no orders from us,” according to Reuters.

    Ukraine’s Interim Prime Minister Arseniy Yatsenyuk has also accused Russian troops of occupying Crimea.

    "A number of military forces of the Russian Federation are deployed in Crimea. We cannot figure out the reason why Russian boots are on Ukrainian ground. And it's crystal clear that it was ordered personally by President Putin,” he told the Associated Press Wednesday. “This is Ukrainian territory and Russia wants to grab control over Crimea. But I will underline again, we will do our best in order to regain control over Ukrainian territory. The Russian military is to be back in the barracks."

    Lavrov said Wednesday that the military personnel of Russia’s Black Sea Fleet are back in their deployment sites, Reuters reports.

    “We will do everything not to allow any bloodshed,” Lavrov said.

    Meanwhile, Deputy U.N. Secretary General Jan Eliasson said a group of unidentified men – some carrying weapons -- surrounded Robert Serry, a special representative of U.N. Secretary General Ban Ki-moon, in the city of Simferopol. Eliasson said the men told Serry that he should leave Crimea.

    “This action should be seriously condemned,'' Eliasson said, according to Reuters.

    A U.N. spokesman later said Serry is taking a flight out of Simferopol and will return to Kiev to continue his mission.

    In Donetsk, the home city of Yanukovych, more than 2,000 people gathered in the square Wednesday afternoon outside the regional administrative building before groups of men broke through police ranks and smashed their way into the building, according to an Associated Press photographer.

    A Russian flag was later seen flying from the roof on the building, Reuters reports.

    It wasn't immediately clear if there were any injuries. Several government buildings around Ukraine, particularly in the east, have been seized by pro-Russian demonstrators in recent days.

    In Kharkiv, around 1,000 pro-Moscow protesters marched.

    Ukraine’s interim prime minister also gave his first sitdown interview to the Associated Press on Wednesday, his spokeswoman said.

    Yatsenyuk said the Crimea region may be granted more local powers and a special task force could be established "to consider what kind of additional autonomy the Crimean Republic could get."

    He blamed Putin for causing one of the sharpest international crises in Europe since the end of the Cold War -- and expressed fears about further possible Russian incursions.

    Asked if he was afraid that Russia might send troops to occupy other Russian-speaking areas of Ukraine, Yatsenyuk said: "Let me put it bluntly: yes, it's still a concern and Russia is to realize its responsibility and Russia is to stick to its international obligation, to stop the invasion.

    Yatsenyuk, who spoke in English, said he hadn't talked personally to Putin, "but it's in the interests of our countries to start a dialogue."

    The top diplomats from Russia, Ukraine, the U.S., Britain and France are not necessarily all at the same table, but French Foreign Minister Laurent Fabius said everyone has been working non-stop for a diplomatic solution for the crisis in Ukraine.

    Fabius said European Union leaders meeting in Brussels on Thursday could decide on sanctions against Russia if there is no "de-escalation" by then, Reuters reported. Canada said Wednesday that it will impose economic sanctions on those who worked for Yanukovych.

    But Russia is already working on a response if it is hit with sanctions.

    The RIA news agency quoted Andrei Klishas, head of the constitutional legislation committee in the upper parliament house, saying that a bill to allow the confiscation of property, assets and accounts of European or U.S. companies "would offer the president and government opportunities to defend our sovereignty from threats."

    Russia took over the strategic Crimean Peninsula on Saturday, placing its troops around its ferry, military bases and border posts. Two Ukrainian warships remained anchored in the Crimean port of Sevastopol on Wednesday, blocked from leaving by Russian ships.

    Russian forces also seized two Ukrainian missile defense battalions, Reuters reported, citing an Interfax news agency report. But the Ukrainian Defense Ministry could not confirm it.

    Fox News’ James Rosen and the Associated Press contributed to this report.