North Korea has tested three short-range missiles, South Korean media say, as concern mounts in the region that a long-range test could be days away.

It test-fired other missiles earlier this week and has incurred fresh UN sanctions since holding a second underground nuclear test in May.

Two of the missiles were fired from a base near Wonsan into the Sea of Japan, South Korea's defence ministry said.

They are believed to have been Scuds with a range of 500km (312 miles).

South Korea's Joint Chiefs of Staff (JCS) said the first two missiles had been fired between 0800 (2300 GMT) and 0830.

The third missile was fired at around 1045, South Korean news agency Yonhap said.

"Our military is fully ready to counter any North Korean threats and provocations based on strong South Korea-US combined defence posture," the JCS said in a statement.

A South Korean defence official said Saturday's tests were of greater concern than Thursday's, as the missiles had longer ranges.

"Thursday's missile tests were apparently made as part of a military drill but today's launches, which came on the eve of the US Independence Day, are believed to be aimed at political purposes," the official told Yonhap.

Nuclear warhead fears

The BBC's John Sudworth in Seoul says the launches are seen there as part of North Korean efforts to ratchet up the tension.

Japanese and South Korean media have reported that North Korea may be preparing to launch another long-range ballistic missile.

There are fears that North Korea is trying to produce nuclear warheads small enough to put on missiles.

After six-nation talks aimed at curbing North Korea's nuclear ambitions broke down earlier this year, Pyongyang said it would "weaponise" its plutonium stocks and start enriching uranium for a light-water nuclear reactor.

On 12 June the UN Security Council approved a resolution allowing inspection of air, sea and land shipments in and out of North Korea suspected of carrying banned arms and weapons-related material.

The North has said it will treat any interception of its ships as a declaration of war.

Source: BBC