YEONPYEONG ISLAND, South Korea — The U.S. and South Korea launched joint war games today as a top official from North Korea’s ally China met South Korea’s president in a bid to calm tensions after a deadly North Korean artillery attack last week.

Hours after the drills began, residents of the South Korean island targeted by last week’s barrage were ordered to evacuate to shelters after the military heard fresh artillery fire north of the disputed western sea border. None of the rounds landed on the island, and authorities later lifted the evacuation order.

Four South Koreans were killed last Tuesday when the North rained artillery on Yeonpyeong Island, home to both fishing communities and military bases, in one of the worst assaults on South Korean territory since the 1950-53 Korean War.

China’s State Councilor Dai Bingguo, a senior foreign policy adviser, met with South Korean President Lee Myung-bak in Seoul, according to Lee’s office, which provided no details. South Korea’s Yonhap news agency said they discussed the North Korean attack and how to ease tensions.

The meeting followed similar discussions Saturday between Dai and South Korean Foreign Minister Kim Sung-hwan, according to Seoul’s Foreign Ministry.

The war games in the Yellow Sea, south of the targeted island, involve the USS George Washington supercarrier and display resolve by Korean War allies Washington and Seoul to respond strongly to any future North Korean aggression. However, Washington has insisted the drills are routine and were planned well before last Tuesday’s attack.

The drills kicked off this morning when ships from both countries entered the exercise zone, an official with South Korea’s joint chiefs of staff said on condition of anonymity, citing office rules.

However, a spokesman for the U.S. military in South Korea said U.S. ships were still steaming toward the area and that the drills would not officially begin until later in the day.

Earlier today, North Korea issued a fresh threat to launch attacks against South Korea if provoked.

“We will launch merciless counter-military strikes against any provocative moves that infringe upon our country’s territorial waters,” the North’s main Rodong Sinmun newspaper said in a commentary carried by the official Korean Central News Agency.

South Korea was investigating the exact location of today’s artillery fire and whether it was part of North Korean exercises, said the joint chiefs of staff official.

At a funeral Saturday near Seoul for one of those killed on Yeonpyeong Island, South Korea’s marine commander, Maj. Gen. You Nak-jun, vowed a “thousandfold” retaliation for the attack.

Passers-by paused at Seoul’s main train station to watch funeral footage on a big screen.

“Once the enemy attacks us, it is our duty to respond even more strongly,” said student Jeon Hyun-soo, 19.

Elsewhere in Seoul, about 70 former special forces troops protested what they called the government’s weak response and scuffled with riot police in front of the Defense Ministry, pummeling the riot troops’ helmets with wooden stakes.

North Korea’s state news agency said that although “it is very regrettable, if it is true, that civilian casualties occurred on Yeonpyeong island, its responsibility lies in enemies’ inhumane action of creating a ‘human shield’ by deploying civilians around artillery positions.”