MOSCOW/KIEV - Russia launched military manoeuvres on its westernmost edge on Tuesday, a day after Nato began war games near the Russian border that Moscow labelled “an act of aggression,” amid simmering East-West tensions over Ukraine.

The Russian defense ministry said military drills involving the Baltic Sea fleet, the air force and paratroopers were under way in Kaliningrad, a Russian exclave sandwiched between EU and Nato members Poland and Lithuania.

“The manoeuvres are taking place just as the international games Saber Strike-2014 and Baltops-2014 began in Europe,” the defense ministry said.

“The number of personnel involved in the Kaliningrad manoeuvres as well as defense ministry hardware are comparable with the number of personnel, weapons and military equipment involved in the drills conducted by Nato member countries on the border.”

Meanwhile, Ukraine’s new Western-backed president Tuesday ordered the creation of humanitarian corridors in the separatist east that could save civilians and advance his plan to end nearly two months of fighting by the end of the week.

Tycoon Petro Poroshenko’s initiative meets a major demand put forward by Moscow and helps address growing concern among rights groups about Kiev’s use of tanks and air power in heavily populated areas to suppress the pro-Russian insurgency. But the 48-year-old chocolatier and political veteran stopped well short of accepting the Kremlin’s request to allow Russian aid into the eastern rustbelt - a move Kiev fears could be used to help arm the rebels. “In order to avoid new victims in the zone of the anti-terrorist operation, the president has ordered the responsible ministers to bring about all necessary conditions for civilians who want to leave,” Poroshenko’s office said in a statement.

The new leader also told his government to provide transportation as well as food and medical supplies for local officials to be able to handle the expected inflow of displaced persons into other parts of Ukraine.

Poroshenko has unveiled plans to end a rebellion that has killed more than 200 and shaken the very foundation of the splintered ex-Soviet state by the end of his first week in office.

The peace push came after the first of what are expected to be daily meetings with Moscow’s ambassador to Kiev and a representative from the Organisation for Security and Cooperation in Europe - a Vienna-based body that was first tasked with ensuring peace during the Cold War.

Poroshenko’s high-stakes negotiations with the Kremlin include efforts to avert a Russian gas cut that would also impact Europe and plunge his economically-devastated country into even deeper recession.

A marathon round of EU-mediated gas talks concluded in Brussels early Tuesday without an agreement but a decision for the sides to meet again by Wednesday after further consultations back home.

But Ukraine’s Energy Minister Yuriy Prodan conceded that little progress had been made on a dispute over prices and billions of dollars in contested debts sought by Moscow.

“We remained at the level of the (last round) of negotiations,” Prodan said.

A top leader in the self-proclaimed “Donetsk People’s Republic” said the level of violence made him doubt the sincerity of Poroshenko’s proposals.

“We heard about this initiative but doubt it will come into force,” Donetsk “deputy governor” Andriy Purgin told Russia’s Interfax news agency.

The government’s military offensive - dubbed an “anti-terrorist operation” by Kiev and a “punitive operation” by Moscow - has gathered considerable momentum since Poroshenko’s May 25 election as the fifth president of Ukraine.

The fighting has engulfed two economically-vital regions that are home to seven million people and have extensive trade and cultural ties to Russia.

The battles are now primarily being waged along Ukraine’s border with Russia and Slavyansk - a city of 120,000 that was the first of a dozen to fall under rebel command in early April.

A Ukrainian military source told AFP that federal forces had also successfully repelled a second attempt by guerrillas to seize the main airport in the neighbouring region of Lugansk since the weekend.

But human rights groups question whether Ukraine’s growing reliance on artillery fire in Slavyansk and neighbouring towns - an offensive backed by Kiev’s US and EU allies - was entirely justified.

“Criminal conduct by the insurgents does not relieve the Ukrainian forces of their obligations to act in accordance with international law,” Human Rights Watch said in a letter addressed to Poroshenko.

The gas talks in Brussels came on the eve of a Russian deadline for Ukraine to cover a debt of $4.5 billion (3.3 billion euros) or have its shipments end Wednesday.

Russia has not yet publically indicated whether it was ready to push back that deadline in an effort to let the negotiations take their course.

Ukraine has refused to pay the gas bill in protest at Russia’s decision to nearly double its rates in the wake of the February ouster of Kiev’s Kremlin-backed president.

About 15 percent of Europe’s gas from Russia transits through Ukraine - dependence that EU nations have been trying to limit following similar disruptions in 2006 and 2009.

Analysts had expected the two sides to agree to a new price of around $350 per thousand cubic metres of gas - a sum about halfway between Russia’s old rate and the one set after the rise to power of the new pro-Western authorities.

But they said Ukraine appeared to be taking a hardline position by demanding the same rate Russia awarded the ousted authorities for their decision to ditch an historic EU trade agreement.

“Ukraine’s lack of a constructive position is seriously impeding the talks,” Moscow’s Alfa Bank said in a morning research note.

“Ukraine continues to insist on a gas price of $268 per thousand cubic metre, which EU authorities view as a non-market price.”

Russia’s energy ministry Tuesday said the talks could proceed if Ukraine covers a $1.45-billion debt it owes from the last two months of 2013 and makes a partial payment of $500 million for April and May deliveries.