KIEV, Ukraine — Ukraine on Friday accused Russia of sending dozens of tanks and other heavy weapons into its rebel-controlled eastern regions and said five servicemen were killed in clashes with the rebels.
Ukrainian National Security and Defense Council spokesman Andriy Lysenko said at least 32 tanks, 16 artillery systems and 30 trucks loaded with fighters and ammunition had crossed into eastern Ukraine from Russia. He said three mobile radar units loaded on trucks also came over the border from Russia.
Lysenko provided no specific evidence and it wasn't immediately clear how his agency had obtained the information, since parts of Ukraine's eastern border with Russia have been under rebel control since August.
Ukraine and the West have continuously accused Moscow of fueling a pro-Russian rebellion in eastern Ukraine with troops and weapons. Russia denies those accusations.
Russia's Defense Ministry had no immediate comment on Lysenko's statement, but earlier Friday it rejected Western allegations that Moscow was deploying more troops near the border.
NATO had no immediate confirmation on the latest Ukrainian report.
"We are aware of the reports of Russian troops and tanks crossing the border between Ukraine and Russia and are looking into these reports," said a NATO military officer, who spoke on condition of anonymity because he wasn't authorized to talk to the media.
"If this crossing into Ukraine is confirmed, it would be further evidence of Russia's aggression and direct involvement in destabilizing Ukraine," the officer added.
He said the alliance had seen "a recent increase in Russian troops and equipment along the eastern border of Ukraine."
German Chancellor Angela Merkel expressed "deep concern" about the reports of Russian troop movements and spoke by phone Friday with Ukrainian President Petro Poroshenko.
According to his office, Poroshenko told Merkel the Sept. 5 truce is being increasingly flouted and complained that Russia had dispatched another humanitarian convoy into Ukraine's rebel-held regions without prior inspection by Ukrainian border officials or coordination with the International Committee of the Red Cross.
Russia's relations with the West have plunged to their lowest point since the Cold War over Moscow's annexation of Crimea and its support for the insurgency in the east. The United States and the European Union have slapped sanctions on Moscow, one of the reasons the value of the Russian ruble has plunged more than 40 percent this year.
Despite the cease-fire, Ukrainian troops and separatist rebels are still fighting near the airport of the main rebel-held city of Donetsk. A funeral was held Friday for two Donetsk teens killed by shelling as they played soccer at their school.
Hostilities also have intensified in the neighboring Luhansk region, where rebels have made some gains in recent weeks. Lysenko said Friday that several villages in the region have come under sustained rebel fire from multiple rocket launchers and artillery. Five servicemen were killed and 16 were injured during the previous day's fighting, he said.
Tensions between Ukraine and Russia rose further after the rebels held an election Sunday that Ukraine and the West denounced as a violation of the truce. Russia welcomed the vote but in carefully chosen language.
Russian President Vladimir Putin's foreign affairs adviser, Yuri Ushakov, emphasized Friday that Moscow's statement saying it "respects" the rebel vote doesn't amount to its recognition. He added that Russia wants peace talks to continue.
On a separate topic, the rebels said Friday that more human remains were found at the crash site of Malaysia Airlines Flight 17 as the plane's wreckage was being removed from the area.
The Boeing 777 was shot down July 17 over eastern Ukraine while flying from Amsterdam to Kuala Lumpur, killing all 298 people on board — most of them Dutch citizens. Ukraine and the West have blamed the pro-Russian separatists, who have denied the involvement. A probe into the crash is continuing.
Vladimir Isachenkov in Moscow, John-Thor Dahlburg in Brussels and Frank Jordans in Berlin contributed to this report.