SEOUL - South Korea's Marine commander on Saturday vowed "thousand -fold" revenge for a North Korean attack that killed two servicemen as protesters demanded tougher action by the government against its reclusive neighbor. The two Marines were honored with a gun salute as families wailed and grim-faced officials saluted the funeral cortege, days after North Korea rained shells on a tiny island in the heaviest attack on South Korea since the 1950-53 civil war. "All Marines, including Marines on service and reserve Marines, will avenge the two at any cost, keeping today's anger and hostility in mind," Lieutenant General Yoo Nak Joon, commander of the South Korean Marine Corps, said, speaking in front of a hearse lightly dusted by snow. "We will put our feelings of rage and animosity in our bones and take our revenge on North Korea." Two Marines and two civilians were killed in the attack. The funeral was followed by three separate anti-North Korea protests in the capital as a US nuclear-powered aircraft carrier headed for joint maneuvers with South Korea on Sunday, infuriating North Korea and prompting a warning from its only major ally, China. "It's time for action. Time for retaliation. Let's hit the presidential palace in Pyongyang," shouted close to 1,000 Marine veterans in downtown Seoul who burned photographs of North Korean leader Kim Jong-il and his anointed successor, son Kim Jung-un. Elsewhere, members of the "Underwater-Demolition Team," practised in sabotage, protested against North Korea and against the government for ignoring their sacrifices on spy missions. Scuffles broke out and police used fire-extinguishers to break up the crowd. President Lee Myung-bak held a meeting of security officials, Yonhap news agency said. South Korea's new defense minister called for tougher action, local media reported. A Seoul newspaper also reported the government plans to sharply increase defense spending next year. "We need to deal with North Korea's provocations strongly," Defense Minister Kim Kwan-jin was quoted as telling presidential aides by the Chosun Ilbo newspaper. "We need to hit back multiple times as hard." Lawmakers have blasted President Lee Myung-bak's government for not responding strongly enough. The defense minister resigned, taking responsibility, and Kim, a career soldier, was appointed in his place. Regional giant China has said it is determined to prevent an escalation of the violence but warned against military acts near its coast as US and South Korean forces prepare for exercises in the Yellow Sea. A North Korean website (http://www.uriminzokkiri) operated by the government propaganda agency said the war drills were "another unforgivable military provocation." "(The North) will make the stronghold of the enemy a sheet of flames if they violate its territory even by 0.01 mm." The US military said the exercises, planned long before Tuesday's attack, were designed to deter North Korea and were not aimed at China. The United States is sending an aircraft carrier group led by the nuclear-powered USS George Washington for the maneuvers with South Korea. "We've routinely operated in waters off the Korean peninsula for years," said Captain Darryn James, a Pentagon spokesman. "These latest provocations have been by the North and they need to take ownership of those, not us." US Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, said North Korea's nuclear ambitions and leader Kim Jong-il's unpredictability increased the threat of regional instability. "It's hard to know why China doesn't push harder," Mullen told CNN television's Fareed Zakaria GPS in comments due to air on Sunday. "My sense is they try to control this guy. And I'm not sure he is controllable." Calling for calm after the attack, Chinese Foreign Minister Yang Jiechi met North Korean ambassador Ji Jae Ryong in Beijing and talked by phone with US Secretary of State Hillary Clinton and South Korean Foreign Minister Kim Sung-hwan. "The top priority now is to keep the situation under control and to ensure such events do not happen again," the Chinese Foreign Ministry said in a statement.