REFILE-UPDATE 2-N.Korea fires artillery near sea border

(Removes extraneous words in para 3)

* North Korea fires dozens of artillery rounds - media

* Colonel-level meeting to discuss warship sinking

* South ends drill, readies for another joint U.S. exercise

* China expresses concern about missing fishing vessel (Adds details)

By Yoo Choonsik and Jeremy Laurence

SEOUL, Aug 9 (Reuters) - North Korea fired a barrage of artillery shells on Monday, some reportedly landing in South Korean waters, adding to already raised tension on the peninsula.

The firings follow the isolated state's recent threat to retaliate with "physical" force to join military drills by its wealthy southern neighbour and the United States.

The prickly North has often turned to sabre-rattling in the past to make a point but analysts doubted it would dare risk all-out war which would pit it against the combined might of the U.S. and South Korean militaries.

South Korea's armed forces demanded the North immediately halt to the firing, and warned of action if it did not, KBS TV quoted unnamed military officials as saying.

It said North Korea had fired more than 100 artillery rounds into its waters off the west coast, near its disputed sea border with the South, soon after the latest military drills by South Korea had ended.

Lieutenant-Commander Yu Jae-il at the Joint Chiefs of Command in Seoul confirmed the firing, but gave no further details.

Earlier this year, the North fired a series of artillery rounds in the same area.

Tension has mounted on the peninsula this year after the sinking of a South Korean warship -- Seoul says it was sunk by a North Korean torpedo -- and a series of military drills by the United States and South Korea.

At the weekend, ties were further strained by the detention of a South Korean fishing boat by a North Korean patrol. Three Chinese nationals were among the seven sailors aboard.

The issue prompted a rare prod of its ally by China which expressed concern over reports its nationals were among those held.

TALKS AND DRILLS

Earlier on Monday, the United Nations Command said North Korean military officials had agreed to a colonel-level meeting at the Panmunjom truce village that straddles the border between the two Koreas.

Tuesday's meeting will be the fourth such talks in a month.

It said the meetings were being held to discuss the date, agenda and protocols for general-level talks on armistice issues related to the sinking of the Cheonan corvette in March, in which 46 sailors were killed.

South Korea, backed by the United States, blames the North for torpedoing the ship. North Korea denies any involvement.

In recent weeks, North Korea and its only powerful ally China have criticised the series of military drills by the United States and South Korea.

Beijing says the drills threaten both its security and regional stability. It has also made public its own recent military drills, events normally kept secret.

The South completed its own naval exercise on Monday, and will next week conduct an exercise with the United States, the second time inside a month they have conducted a joint drill. (Additional reporting by Chris Buckley in Beijing; Editing by Jonathan Thatcher)