In an act of defiance, North Korea fired artillery shots Friday within sight of Yeonpyeong island, which it had attacked earlier this week.

The apparent military drill Friday came as the top U.S. commander in South Korea, Gen. Walter Sharp, toured the island to survey the wreckage from artillery fire three days earlier and as a U.S. nuclear-powered aircraft carrier headed toward the Yellow Sea for exercises next week with South Korea.

The North sees the U.S.-South Korean drills as a major military provocation. Pyongyang unleashed its anger over the planned exercises in a dispatch earlier Friday. “The situation on the Korean peninsula is inching closer to the brink of war,” the report in the North’s official Korean Central News Agency said.

South Korea’s government, meanwhile, struggled to recoup from the surprise attacks that killed four people, including two civilians, and forced Defense Minister Kim Tae-young to resign Thursday. President Lee Myung-bak on Friday named former Joint Chiefs of Staff chairman Kim Kwan-jin to the post.

Washington and Seoul have pressed China to use its influence on Pyongyang to ease tensions amid worries of all-out war. A dispatch Friday from Chinese state media saying Beijing’s foreign minister had met the North Korean ambassador appeared to be an effort to trumpet China’s role as a responsible actor and placate the United States and the South.

About 200 South Koreans held a rally Friday in Seoul to denounce the government’s response to the Yeonpyeong island attack as too weak. Similar recriminations have come from opposition lawmakers and even members of Lee’s own party.

South Korea assured a meeting of the European Olympic Committees on Friday that it would be able to ensure security at the 2018 Winter Games if it’s picked. The Pyeongchang 2018 bid committee presented its case Friday in Belgrade.

The Associated Press contributed to this report.