U.S. Secretary of State John Kerry turned down an invitation to meet his Russian counterpart in Moscow this week and will only "engage in person" when it appears Russia is serious about international proposals for a solution to the Ukraine crisis, the U.S. government says.

Kerry is awaiting a response from Moscow to calls for Russia and Ukraine to hold direct talks and to proposals for an international contact group to sponsor those talks, State Department spokeswoman Jen Psaki says.

"The United States needs to see concrete evidence that Russia is prepared to engage on the diplomatic proposals we have made to facilitate direct dialogue between Ukraine and Russia and to use international mechanisms like a contact group to de-escalate the conflict," she says.

Russia's Foreign Ministry said on Monday it was outraged by lawlessness in eastern Ukraine, and accused the far-right paramilitary movement Right Sector of "conniving" with the new government in Kiev.

Ukraine denied the allegation, and dismissed as untrue Moscow's accusations of misdeeds in its eastern regions.

In its latest salvo in a propaganda war over Ukraine, in which the United States has issued a list of what it calls 10 false claims by President Vladimir Putin, Russia accused the West of being silent over violence and detentions taking place there against Russian compatriots.

The ministry said in a statement masked men had opened fire on peaceful demonstrators in the eastern city of Kharkiv on March 8, wounding some.

It also said seven Russian journalists had been detained in the eastern city of Dnipropetrovsk, suggesting the new leaders and their Western allies were not committed to media freedoms.

"The shamefaced silence of our Western partners, human rights organisations and foreign media is surprising. It raises the question - where is the notorious objectivity and commitment to democracy?" it said.

Ukraine's Foreign Ministry issued a lengthy rebuttal expressing "surprise" at the Russian statement. It denied that shots had been fired and demonstrators wounded in Kharkiv and said it had no confirmation that journalists had been detained.

"It is a pity that in this situation the Russian Foreign Ministry, instead of carrying out its foreign policy duties and ensuring that Russia meets its international obligations, has taken on the mission of systematic disinformation...," it said.

Ukrainian and foreign reporters, it said, were "encountering obstacles to their legal professional activities ... direct threats and even aggressive acts of force, beatings and robberies."

Kharkiv police said they were treating the Kharkiv incident as a minor one and say the only link to Right Sector came from an anonymous phone caller.

Ukraine's government and Western leaders have accused Russian officials and media of distorting the facts to portray the protesters who ended Moscow-backed President Viktor Yanukovich's rule as violent extremists.

Witnesses in eastern Ukraine say tensions have been stoked by pro-Russian activists stirring violence to provide Putin with a justification for invading Ukraine to protect Russians there.

An official who monitors media freedom for The Organisation for Security and Cooperation in Europe (OSCE) said after visiting Crimea last week that her more pressing concern was about media freedoms in the southern Ukrainian region.

She said pro-Russian authorities who have seized power in Crimea were clamping down on media that did not support them and were intimidating reporters.

UN discourages provocation

Secretary-General Ban Ki-moon said Monday he is urging all parties in Ukraine "to refrain from hasty actions and provocative rhetoric."

The UN chief warned that "at this crucial juncture, we cannot afford either miscalculations or inaction."

Ban warned in a statement Monday that "a further deterioration of the situation would have serious repercussions for the people of Ukraine, the region and the global community."

He said a resolution to the crisis must be based on the principles of the UN Charter including "the peaceful settlement of disputes and respect for the unity, sovereignty and territorial integrity of Ukraine."

UN spokesman Stephane Dujarric said Assistant Secretary-General for Human Rights Ivan Simonovic is in Kiev. He will be going to Kharkiv in the pro-Russian east and then to Crimea later this week.

Meanwhile, NATO has authorized AWACS reconnaissance flights over Poland and Romania to monitor the crisis in nearby Ukraine, alliance official said Monday.

"These flights will enhance the alliance's situational awareness," the official said on the condition of anonymity, adding that they "will take place solely over alliance territory."

The decision by the 28 ambassadors to NATO "is an appropriate and responsible action, in line with NATO's decision to intensify our ongoing assessment of the implications of this crisis for alliance security," the official said.

Crimea invites observers

Ukraine's Crimea region has invited the Organization for Security and Cooperation in Europe (OSCE) to send a mission to observe Sunday's referendum on joining Russia, Russia's RIA news agency said on Monday.

It said the invitation had been issued to the Vienna-based security and human rights organization by the region's pro-Russian parliament.

But later in the day, a OSCE spokeswoman said Crimea could not invite observers as the region was not a full-fledged state and therefore not a member of the 57-member organisation.

"As far as we know, Crimea is not a participating state of the OSCE, so it would be sort of hard for them to invite us," she said.

She also said that Ukraine, which is an OSCE member, sent no invitation and that the organisation "respects the full territorial integrity and sovereignty of Ukraine".

For the past week, OSCE military observers have been unable to enter Crimea, which is controlled by Russian forces.

On Monday, Sergei Aksyonov, Crimea's newly appointed Prime Minister contested by central authorities in Kiev, said that the pro-Russian authorities in the region "have cordially asked" OSCE observers to leave.

Ukraine, meanwhile, has asked the Council of Europe human rights watchdog to help investigate the clashes that led to President Viktor Yanukovich's overthrow and to monitor minorities in Crimea.

