North Korea continues to deny any involvement in the incident which killed 46 South Korean sailors [AFP/Yonhap]

South Korea has marked the first anniversary of the sinking of its warship, Cheonan, in which 46 sailors were killed.

Thousands attended a memorial service in the central city of Daejon including the families of the dead and Lee Myung-bak, the South Korean president, who burned incense and offered flowers.

"You gave us courage even when you are in pain," Lee said as he consoled the mother of a dead sailor, who donated all the $90,000 compensation money she had received from the government to help buy weapons for the navy.

Speaking during the ceremony, Park Sung-choon, the minister of South Korean patriots and veterans affairs, called for unity among the Korean people.

"The goal North Korea is seeking by its provocations is the division within our society.

"We should rather appreciate the sacrifices the Cheonan ship soldiers made by uniting our hearts as one," Park said.

South Korea accuses the communist North of sinking the 1,200-tonne corvette on March 26 last year near the disputed Yellow Sea border, killing 46 sailors. Pyongyang denies the charge.

Show of strength

The South marked Saturday's memorial by carrying out live fire naval drills in a show of strength against the North.

The Yonhap news agency said authorities warned of drills in the Yellow Sea and off the southern coast, but well south of the disputed sea border.

It quoted a military source as saying that all three of South Korea's naval fleets will conduct exercises until Sunday, simulating attacks by North Korean submarines, ships and aircraft.

A multinational probe in May led by South Korea concluded that a submarine-launched North Korean torpedo sank the Cheonan.

Investigators said they had "overwhelming" evidence, including a partial torpedo motor and propeller said to have been dredged from the seabed. They said this matched a type that the North had previously offered for export.

On Saturday Pyongyang again denied it had anything to do with the tragedy, accusing Seoul of "framing" the North.

State-run official daily Minju Joson said the South had been using the incident over the past year to drum up anti-Pyongyang sentiment and reject inter-Korean talks.

The South, which has remained technically at war with its nuclear-armed neighbour since the Korean conflict ended in 1953 with an armistice, rather than a formal peace accord, says its drills are defensive.

The two Koreas came close to hostilities when the North shelled a border island in November last year, killing two soldiers and two civilians, in protest at military drills near the disputed sea border in the Yellow Sea.

Source: Agencies