In an interview, Russian President Vladimir Putin calls for immediate talks between pro-Russian rebels and Kiev, on issues including “statehood” for eastern Ukraine. (Reuters)

In an interview, Russian President Vladimir Putin calls for immediate talks between pro-Russian rebels and Kiev, on issues including “statehood” for eastern Ukraine. (Reuters)

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 the fight must go on to “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 separatist 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 its Western allies have surmised that Russian forces are significantly aiding pro-Russian separatists.

“Russia is intervening overtly in Ukraine,” NATO Secretary General Anders Fogh Rasmussen said Monday, announcing that the alliance would design a “readiness action plan,” complete with a rapid-response force, at its upcoming summit in Wales to respond to “Russia’s aggressive behavior.”

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The 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 it pulled back from Ukraine.

But Russia maintains that the E.U. threats 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 in Moscow on Monday, pushing for a cease-fire and dismissing Europe’s threats as “sanction inertia.”

Lavrov also scoffed at the idea that pro-Russian militias would surrender their weapons to Kiev, which he said would be tantamount to “destroying themselves,” even as he pledged that “there will be no military intervention” from Russia.

But Ukraine maintains that an intervention is well underway.

Ukrainian President Petro Poroshenko on Monday accused Russia of launching “direct and open aggression” against Ukraine, which he said changed “the situation in the zone of conflict in a radical way.”

A spokesman for Ukraine’s military said Russian forces fired on troops at the Luhansk airport Monday and are supporting the separatists surrounding Ilovaysk, where hundreds of Ukrainian troops have been trapped for more than a week. Russian officials have accused Kiev of not taking advantage of the separatists’ offer to let the troops out via a humanitarian corridor, in exchange for disarming.

The presidents of the European Commission and Ukraine cautioned Russia on Saturday against escalating the conflict in eastern Ukraine. (Reuters)

During a Monday visit to Kiev, Sen. Robert Menendez (D-N.J.) called for the international community to respond by better arming 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 spur a negative response from Russia, listing significant events of the conflict, including Russia’s annexation of Crimea in March , the downing of Malaysia Airlines Flight 17 and the recent battles in the east, to make his case

“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 [Russian President Vladimir] Putin doesn’t care for he sees in the Ukrainian people’s desire to turn to the West.”

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 rebel leader in Donetsk — told the Russian news service Interfax that separatists intended to seek “recognition of our independence” during the talks. The Monday discussions yielded little progress.

Putin said in a television interview that aired Sunday that “statehood” for eastern Ukraine should be part of talks 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 Kiev government, 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 stressed that a resolution to the conflict “largely depends on the political will of today’s Ukrainian leadership,” but said he did not expect the fighting to stop before Ukraine’s parliamentary elections, set for Oct. 26.

Once elected, Ukraine’s new parliament is expected to vote on a law to end the country’s nonaligned 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.

Annie Gowen in Mariupol contributed to this report.