Russia has said it is drafting counterproposals to a US plan for a negotiated solution to the Ukraine crisis. The Kremlin denounced the new western-backed government as an unacceptable “fait accompli” and claimed Russian-leaning parts of the country had been plunged into lawlessness.

The Kremlin moves came as Russian forces strengthened their control over Crimea, less than a week before the strategic region is to hold a contentious referendum on whether to split off and become part of Russia.

In a televised briefing with President Vladimir Putin, the Russian foreign minister, Sergey Lavrov, said proposals made by John Kerry, the US secretary of state, were “not suitable” because they took the situation created by the coup as a starting point, referring to the ouster of Ukraine’s pro-Kremlin president, Viktor Yanukovych.

Referring to a document he received from Kerry explaining the US view of the situation in Ukraine, Lavrov said: “To be frank it raises many questions on our side … Everything was stated in terms of allegedly having a conflict between Russia and Ukraine, and in terms of accepting the fait accompli.”

Lavrov said Kerry had delayed a visit to Moscow to discuss the situation and Russia had decided to prepare new proposals of its own, though he did not say what they were. “We suggested that he come today … and we were prepared to receive him. He gave his preliminary consent. He then called me on Saturday and said he would like to postpone it for a while,” the minister said.

But in Washington state department officials said it was Russia’s refusal to discuss the American proposals that was hurting prospects for a negotiated solution, in particular the idea of direct talks between Russian officials and those of the new Ukrainian government.

“We are still awaiting a Russian response to the concrete questions that Secretary Kerry sent Foreign Minister Lavrov on Saturday in this regard,” Jen Psaki, a state department spokeswoman, said in a statement.

“Secretary Kerry made clear to Foreign Minister Lavrov that he would welcome further discussions focused on how to de-escalate the crisis in Ukraine if and when we see concrete evidence that Russia is prepared to engage on these proposals.”

The US statement said Kerry, in weekend discussions with Lavrov, reiterated Washington’s demand that Moscow pull back its troops from Ukraine and end attempts to annex the Crimean peninsula. Kerry also called on Russia to cease what the statement described as “provocative steps” so that diplomatic talks could continue.

US officials described a series of diplomatic manoeuvres between Washington and Moscow over the weekend that initially led to an invitation for Kerry to meet with Putin on Monday. The offer expired, however, after the two sides could not quickly agree to a page-and-a-half outline for potential negotiations that, above all, demanded Ukraine’s borders remain intact, according to the officials who were not authorised to be quoted by name.

The US outline did call for ways to address any Russian concerns about the government turnover in Kiev that Moscow is calling a coup, and it introduced the potential for investigations into acts of violence by any party to the conflict, the officials said. Left unsaid, however, was precisely how those concerns might be assuaged or what government would be tasked with leading such an investigation.

The US outline also called on Russia to pull back from Crimea, both in military force and in influence, to halt the local government there from holding a 16 March vote on whether it should separate from Ukraine, the officials said. It further sought to gain Russian support for placing international monitors in Crimea, allowing the International Monetary Fund to work with Ukraine and backing a 25 May national election called by Kiev.

Ukraine’s foreign minister said on Monday that his country was practically in a state of war with Russia, whose forces have effectively taken control over the Crimean Peninsula in what has become Europe’s greatest geopolitical crisis since the end of the cold war. “We have to admit that our life now is almost like … a war,” the Ukrainian foreign minister, Andrii Deshchytsya, said before meeting his counterparts from Belgium, the Netherlands and Luxembourg. “We have to cope with an aggression that we do not understand.”

Ukraine’s prime minister, Arseniy Yatsenyuk, is to meet with President Barack Obama in Washington on Wednesday.

On Monday the Russian foreign ministry denounced the lawlessness it said “now rules in eastern regions of Ukraine as a result of the actions of fighters of the so-called Right Sector, with the full connivance” of Ukraine’s new authorities. Right Sector is a grouping of far-right and nationalist factions whose activists were among the most radical and confrontational during the three months of demonstrations in the Ukrainian capital, Kiev, that eventually led to Yanukovych fleeing the country.

Pro-Russia sentiment is high in Ukraine’s east and there are fears Russia could seek to incorporate that area as well.

