A convoy of 50 orange-colored South Korean trucks streamed into North Korea across the tense border on Saturday, carrying emergency fertilizer aid to the impoverished communist country.

The shipment is part of 200,000 tons of fertilizer South Korea promised to give to the North without conditions during a high-level meeting that concluded on Thursday. North Korea, on its part, has promised South Korea to resume suspended inter-Korean Cabinet-level talks in Seoul on June 21-24, where the nuclear issue is certain to be raised again.

Seoul plans to send 10,000 tons of fertilizer by land and the remaining amount by ship.

The delivery marked the first time the North temporarily opened its land border this year to receive aid. Last year the North opened its border to receive South Korean rice.

The inter-Korean border is the world's most heavily fortified, with nearly 2 million troops deployed on both sides. The Koreas are still technically at war, having signed no peace treaty at the end of the Korean War which lasted from 1950 to 1953.

Ko Gyoung-bin, the Director-general in charge of South Korea's Unification Ministry's social and cultural exchanges bureau, said the trucks will carry 1,250 tons of fertilizer daily to North Korea until May 27.

Shipment by sea will begin four days later, Ko said, adding that freighters from both Koreas will be used.

So far, South Korea has given 1.55 million tons of fertilizer to North Korea, which is short an average of one million tons of fertilizer every year.