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Michel Euler, Associated Press
Ukrainian President Petro Poroshenko shows a piece of a bus that was attacked recently during the panel "The Future of Ukraine" in Davos, Switzerland, Wednesday, Jan. 21, 2015. The meeting runs Jan. 21 through 24 under the overarching theme "The New Global Context".

MOSCOW — Moscow proposed Wednesday that both Ukraine and the pro-Russian rebels pull heavy weapons back to a previously agreed-upon division line to help reduce hostilities, but said nothing about the rebels surrendering any territory they gained by violating the peace deal.

On the ground, fighting between Ukraine and the rebels appeared to be roaring toward another major confrontation in eastern Ukraine. The Russian-backed separatists sent large amounts of weaponry all day Wednesday toward another flashpoint near Luhansk, 50 kilometers (30 miles) west of the Russian border.

Russian Foreign Minister Sergey Lavrov, who was to meet with his Ukrainian, French and German counterparts in Berlin later in the day, said the proposed withdrawal of artillery should help end the surge in fighting to control Donetsk's airport and other flashpoints.

Moscow has denied Ukrainian and Western claims that it provides manpower and arms to the separatists but has acknowledged that some Russians have joined the insurgents. Yet the sheer amount of sophisticated heavy weaponry in insurgent hands is widely seen in the West as irrefutable evidence of Russia's direct involvement.

The now-destroyed Donetsk airport has been the focus of fighting for months because of its strategic location and symbolic value, part of fighting in eastern Ukraine has killed more than 4,700 people since April.

Northwest of Luhansk, the second largest rebel-held city, the Ukrainian government and the rebels were fighting over two checkpoints on a strategic highway. Ukraine's Defense Ministry said one of those positions, Checkpoint 31, had been abandoned but operations were underway to retake it.

Separatist forces heavily bolstered their offensive capabilities there throughout the day Wednesday.

Ukrainian President Petro Poroshenko spoke Wednesday at the World Economic Forum in the Swiss resort of Davos but was cutting short his visit due to the Luhansk developments. In an interview with CNBC in Davos, Poroshenko emphasized the need to close the Russian-Ukrainian border and withdraw Russian troops from Ukraine.

Around midday, an AP reporter saw nine Gvozdika self-propelled howitzers and six anti-tank cannons moving near the eastern Ukrainian town of Perevalsk. A rebel militiaman with the convoy, who declined to provide his name, said the armament heading in the direction of Checkpoint 31.

Along the same road, the AP saw four Grad multiple rockets launchers accompanied by four trucks carrying ammunition and 15 pristine-looking tanks, also heading toward the checkpoint.

Ukrainian Foreign Ministry spokesman Yevhen Perebyinis says separatist forces had seized 500 square kilometers (190 sq. miles) of territory since the division line was agreed upon at September talks in Minsk, the capital of Belarus.

Lavrov said continuing violations of a truce in eastern Ukraine were rooted in the failure to respect the September division line. Lavrov said Russian President Vladimir Putin had written to Poroshenko proposing to use the original division line for the withdrawal of heavy weapons.

Lavrov acknowledged that the rebels had made some gains and said using the original line of separation would help de-escalate the fighting and allow the parties to resume talks on other issues.

"We need to fulfill the main goal: protect the civilian population," Lavrov said.

Although he said Russia had persuaded the rebels to withdraw heavy weapons to the original line, he said nothing about the rebels giving up any territorial gains.

Poroshenko said a political dialogue must follow to help stabilize the situation and called for holding local elections in the east in line with the Ukrainian law. Lavrov said Russia would welcome municipal elections in eastern Ukraine.

The escalation of hostilities derailed a planned meeting of the leaders of Russia, Ukraine, France and Germany earlier this month. German Chancellor Angela Merkel emphasized that such a summit could only be held if it could achieve specific results.

"We don't want another presidential-level meeting that doesn't produce a result in the end, so I hope that today a few structures can emerge," she said Wednesday.

Chernov reported from Perevalsk. Peter Leonard in Kiev, Ukraine and Frank Jordans in Berlin contributed to this report.