China warned Friday against military activity in its exclusive economic zone, ahead of weekend US-South Korean exercises intended as a show of force against Beijing's ally North Korea.

"We hold a consistent and clear-cut stance on the issue. We oppose any party to take any military actions in our exclusive economic zone without permission," foreign ministry spokesman Hong Lei said in a statement.

Beijing said Thursday it opposed the war games, which come after North Korea on Tuesday fired a barrage of artillery shells at a South Korean island, as Premier Wen Jiabao warned against "provocative" acts.

Tensions are high in the region after Tuesday's attack, which left four people dead and prompted retaliatory fire from the South.

The United States and South Korea, which have both appealed to Beijing to use its influence to rein in its wayward ally, are planning a four-day naval show of force against North Korea that will involve a US aircraft carrier.

China has previously come out strongly against such exercises in its backyard, saying they risk exacerbating tensions.

South Korea said Thursday it would seek cooperation from China and Russia over the issue.

Beijing, which is North Korea's closest ally and source of economic support, has so far refused to take sides, merely calling for "restraint" from all parties.

The South is weighing what support it will get from Russia and China before deciding whether to refer Tuesday's attack to the UN Security Council, where Beijing and Moscow hold veto power as permanent members.

Earlier this year, China blocked efforts by South Korea and other nations to secure UN condemnation of North Korea over the torpedoing of a South Korean naval ship that was blamed on Pyongyang, in which 46 sailors died.