Seoul: South Korea welcomed expanded US financial sanctions against North Korea on Tuesday, but made its first large-scale offer of aid to its destitute neighbour since the sinking of one of its warships in March.

President Barack Obama broadened financial sanctions on North Korea on Monday and froze the US assets of four North Korean citizens and eight firms in part to punish the diplomatically isolated state for the sinking of Cheonan corvette which killed 46 sailors.

US officials hope the measures, which target North Korean entities that trade in conventional arms and luxury products and that counterfeit US currency, will also sharpen pressure on the North's leader Kim Jong-il to abandon his nuclear programmes.

Washington views the atomic capabilities of the North, which tested nuclear devices in 2006 and 2009, as a threat to its allies South Korea and Japan, and as a proliferation risk.

Pyongyang has said it wants to restart stalled nuclear disarmament talks, but both Seoul and Washington insist it accepts responsibility for the sinking of the Cheonan before they engage in dialogue.

A foreign ministry spokesman in Seoul welcomed the toughened US sanctions. "It can be assessed that the US sanctions regime on North Korea has been completed overall," he said.

At the same time, Seoul made a conciliatory gesture to Pyongyang by offering 10 billion won (Dh30.89 million) in aid to its flood-hit neighbour. The offer, if accepted by Pyongyang, would be the first large-scale aid from Seoul after the sinking of its warship that the South blames on a submarine attack by the North.

Heavy rains in July and August hit the North's northern region bordering China and its eastern provinces, forcing thousands from their homes and putting farmland under water.