A Russian aid convoy that has been stalled on the border was finally allowed to pass Thursday, Reuters reported.

Only 16 of about 280 trucks arrived on Sunday with 2,000 tons of humanitarian aid, according to BBC, and it was unclear how the Ukrainian government was going to gain access to them.

Some had concerns that it was to serve as a Trojan horse to smuggle military supplies to rebels, according to Reuters.

The trucks are entering an area referred to as "no-man's land" between the two countries, and are being allowed following days of heavy artillery in Ukraine, according to The New York Times.

Convoys leaving the rebel-held areas in Ukraine were attacked with rockets and other Russian weapons -- which killed many civilians and were along the route taken by the aid trucks, according to the Associated Press.

Since power in the area is limited, independent confirmation of the attacks was not available, but the U.S. warned both sides that they needed to take care not to harm innocent lives.

Sergey Karavaytsev, an official in the Russian Emergencies Ministry, told the NYT the trucks would be checked by the Russian border service, Ukrainian border guards and representatives of the International Red Cross.

The trucks are carrying water, canned meats, baby food and other goods from the Red Cross.

But Ukrainian officials have been critical of the convoy and allege that some of the items are useless, stating that many of the trucks are half full and carrying items like 30 tons of salt, according to the NYT.

The destination of the aid is unknown, but the conflict so far has claimed more than 2,000 lives and forced more than 340,000 people to flee their homes near the border, according to AP.