AMMAN, Jordan -- The United Nations has begun sending desperately needed aid from Jordan to hundreds of thousands of civilians in war-torn Syria.

The U.N.'s humanitarian office said on Sunday that 369 trucks will carry one month's worth of supplies to Syria. It's the first cross-border aid shipment since the Syrian government recaptured a trade crossing with Jordan from Syrian rebels and reopened it in October.

Anders Pedersen, a top U.N. humanitarian official in Jordan, says the aid is being delivered in a "major logistical operation" aimed at mitigating the suffering of Syrians.

Pedersen says the U.N. agency expects the aid to reach 650,000 Syrians.

The U.N. says about 13 million Syrians suffering from the fallout of the country's seven-year civil war are in urgent need of food, water, and medical supplies.