South Korea resumed official economic assistance to North Korea on Tuesday as tensions eased over Pyongyang's nuclear program, sending a shipload of fertilizer to the impoverished nation.

A Vietnamese-registered cargo ship left the southwestern port of Yeosu for North Korea carrying 6,500 tons of composite fertilizer — the first batch of a 300,000-ton shipment, said Kim Nam-sik, a spokesman for the Unification Ministry.

The South's official aid to North Korea has been suspended since July when North Korea test-fired a series of missiles, although some emergency relief supplies were later sent to help the North cope with heavy floods.

Aid was kept on hold in the wake of Pyongyang's nuclear test in October, but ties between the Koreas improved markedly after North Korea promised in international disarmament talks last month to take initial steps to dismantle its atomic programs.

Following the Feb. 13 landmark deal that calls for the North to shut down its main nuclear reactor in exchange for economic and political incentives, the two Koreas resumed high-level reconciliation talks for the first time in more than seven months.

Despite the fertilizer aid, South Korea plans to hold off on resuming rice shipments until after mid-April to make sure North Korea carries out its promise to close the nuclear reactor.

South Korea has been a main aid provider for the North, sending 2.25 million tons of fertilizer and 2.29 million tons of rice since the mid-1990s.

The two sides remain technically at war because the 1950-53 Korean War ended in a truce, not a peace treaty. But reconciliation bloomed after 2000 when their leaders held their first and only summit.