Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
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(CNN) – In Donetsk they are burying the dead after a fragile September ceasefire fatally frays.
Mourners Friday at a Russian orthodox church wept as they laid to rest two teenagers killed in a shelling attack near the airport in Donetsk Wednesday. The teens are two of more than 4,000 who have been killed in what is looking like proxy war between Russian President Vladimir Putin and Ukraine's government.
After annexing Crimea, Russian-backed separatists have been battling Ukrainian government forces for months in the eastern part of the country, with heavy support from Moscow.
While there have been some sanctions against Russia as a result of its aggressive moves in Ukraine – coupled with the shooting down of a passenger plane by the rebels – critics say the consequences have been insufficient.
And now Ukrainian officials say Russian tanks are again rolling across the border between the two countries.
"The movement of military equipment consisting of 32 tanks, 16 D30 Howitzer artillery systems, and 30 Kamaz trucks carrying ammunition and fighters was reported," Ukrainian defense and security council spokesman Andriy Lysenko said.
The heavy equipment came through the volatile Luhansk region, Ukrainian officials said.
In Moscow the Kremlin called the reports unfounded and "provocative."
But watchers of the region say this fits a pattern of Putin throwing his weight around with impunity, knowing no country outside of Ukraine is willing to sacrifice one soldier to stop him.
"President Putin is calculating in the long run he can get away with this, and that he can get away with doubling down, and continue to take more territory in Ukraine," said The Atlantic Council's Damon Wilson.
NATO Secretary General Jens Stolten said earlier this week they were aware of a build up of Putin's troops on the border.
"Russia continues to support the separatists by training them, by providing equipment and supporting them, also by having special forces, Russian special forces inside the eastern parts of Ukraine," Stolten said.
The apparent uptick in military action comes just one week after rebel elections in Donetsk, where only pro-Russian separatists were on the ballot, and one week before the G20 is set to meet in Australia.
"We aren't there yet on the right kind of strategy, the Western strategy, that's ultimately going to deter Putin. We've got to find the right approach that deters him, that stops him from further aggression. While sanctions are an important element, it's clearly not sufficient," said Wilson.
If Russia has indeed sent more troops and equipment into Ukraine, will the international community respond?