MOSCOW — Russian officials pressed Ukraine on Monday to declare a cease-fire with separatists, but Ukrainians say they are locked in a war not just against the rebels but also against Russia — on behalf of Europe.
‘‘A great war has come, the likes of which Europe has not seen since the Second World War,’’ Ukrainian Defense Minister Valeriy Heletey said on his Facebook page Monday, adding that Ukraine must keep fighting and ‘‘show that Ukrainians are not going to give up.’’
Lost territory, trapped soldiers, and increasing reports of Russian tanks and troops operating in eastern Ukraine have changed the course of events in the past few days. Newly emboldened rebel forces are bearing down on strategic targets, such as the port city of Mariupol — which the Ukrainian military maintains it can defend — and the airport in Luhansk, where troops retreated in the face of a rebel onslaught Monday.
Ukraine and Western allies have surmised that the pro-Russian separatists are not acting alone and that Russian forces are providing significant assistance.
‘‘Russia is intervening overtly in Ukraine,’’ NATO Secretary General Anders Fogh Rasmussen said Monday, announcing that the alliance would draft a ‘‘Readiness Action Plan’’ at its upcoming summit in Wales to respond to ‘‘Russia’s aggressive behavior.’’
That summit will coincide with a self-imposed deadline from the European Union to announce further economic sanctions against Russia. European leaders agreed over the weekend to slap Russia with new measures within a week, unless Russia pulled back from Ukraine.
But Russia maintains that the threats from Europe are weak — and that it is not militarily involved in the Ukraine conflict.
‘‘Let’s sit down and talk, not threaten sanctions,’’ Russian Foreign Minister Sergei Lavrov said during an address to university students on the first day of the Russian school year, dismissing Europe’s threats as ‘‘sanction inertia’’ and scoffing at the idea that pro-Russian militias would surrender their weapons to Kiev, a move tantamount to ‘‘destroying themselves.’’
Instead, he chided Europe and the United States for supporting a Ukrainian government that would fire on its own people, cities, schools and hospitals.
But Ukrainian officials say the heavy forces operating in eastern Ukraine are coming from across the border with Russia.
Lysenko charged that four battalions of the Russian armed forces are on Ukrainian territory, saying that each battalion included almost 400 soldiers, artillery and supportive aircraft.
During a Monday visit to Kiev, Sen. Robert Menendez, D-N.J., called for the international community to better arm Ukrainian troops.
‘‘It’s great to provide night-vision goggles,’’ Menendez said at a news conference, referencing one form of assistance the United States approved to send to Ukrainian troops this summer. ‘‘But what can you do if all you can do is see them but you can’t defend yourself against their attacks?’’
He dismissed concerns that arming Ukraine would provoke a negative response from Russia.
‘‘There should be no concern that providing the Ukrainians with the wherewithal to fight for themselves would be provocation,’’ Menendez said, listing significant events of the conflict, from Russia’s annexation of Crimea in March, to the downing of Malaysia Airlines Flight 17, to the recent battles in the east — all of which he blamed on Russia.
‘‘Russia has done all of this without any provocation,’’ he said. ‘‘From my perspective, this is a Russian fight against Europe being fought out on Ukrainian territory — everything Putin doesn’t care for he sees in the Ukrainian people’s desire to turn to the West.’’
But pro-Russian rebels are stepping up their demands, too. Ahead of a meeting in Minsk, Belarus, among Kiev representatives, separatists and their interlocutors, Andrei Purgin — a leader among rebels in Donetsk — said the separatists intended to seek ‘‘recognition of our independence’’ during the talks.
The separatists declared independent republics in Luhansk and Donetsk months ago, but Moscow has not formally recognized them.
Russian President Vladimir Putin said in a television interview that aired Sunday that ‘‘statehood’’ for eastern Ukraine should be part of discussions to resolve the conflict, but he has repeatedly insisted that he wants greater autonomy for the region, not the breakup of Ukraine — despite Russia’s seizure of Crimea.
In the interview, Putin scoffed at Europe’s support for the government in Kiev, arguing that it ran counter to purported European values.
‘‘What are the so-called European values?’’ Putin asked. ‘‘Maintaining the coup, the armed seizure of power and the suppression of dissent with the help of the armed forces? Are those modern European values?
‘‘Our colleagues need to remember their own ideals,’’ he said.
Putin called for an end to the hostilities but stressed that a resolution ‘‘largely depends on the political will of today’s Ukrainian leadership.’’
But he said he did not expect the fighting to stop as Ukraine heads into a parliamentary election season.
Ukrainian President Petro Poroshenko recently called for the dissolution of parliament and new elections, scheduled for Oct. 26.
Once elected, Ukraine’s new parliament is expected to vote on a law to end the country’s non-aligned status, paving the way for it to eventually apply for NATO membership.
Rasmusssen told reporters Monday that Ukraine’s chances of being adopted as a member depend on whether the country can meet various criteria.