A South Korean cargo plane has arrived in the North, laden with emergency aid for the victims of last week's train disaster.
The first delivery arrived by ship
The first ever cargo flight between the two countries landed at Sunan airport near Pyongyang, airline officials said.
The flight is in addition to $25m of aid which Seoul plans to send by ship.
More than 160 people died in last Thursday's explosion, sparked when a train carrying oil and chemicals hit power lines in the town of Ryongchon.
Nearly 400 victims remain in hospital - many of them children - and aid workers have warned that the death toll could get even higher.
North Korea estimates that $350m of damage was caused by the blast, and has made a rare appeal for outside aid.
Many countries have responded in addition to South Korea - including Russia, the US, China, Australia, Germany and Japan.
The South Korean cargo plane which arrived on Friday contained 70 tonnes of emergency aid, including medical kits, blankets and bottled water, worth a total of 550m won ($470,000).
The flight was agreed on Wednesday, after a first consignment of South Korean relief goods was dispatched by sea.
The ship - loaded with instant noodles, blankets
and bottled water - arrived in the North Korean port of Nampo on Thursday.
Seoul had first hoped to use an overland route to deliver aid, but the North turned down this offer, apparently out of security concerns over the tense military border that divides the two Koreas.
Seoul has also agreed to send US$25m in
building materials, food and other goods to Ryongchon.
The list of items requested by North Korea includes 50,000
tons of cement, 10 bulldozers, five steam shovels, 500 tons
of diesel fuel oil, 500 tons of gasoline, 1,500 school desks and chairs and even 50 television sets.