North Korea accuses South of using 'human shields'
North Korea has accused Seoul of using human shields on the island where firing from the North killed two South Korean civilians this week.
The North's state media said the South was using the deaths for propaganda.
Two marines also died in the shelling of the South's Yeonpyeong island. Their funerals were held on Saturday amid rising anger in the South.
The North has also issued a new warning on US-South Korea military exercises, set to start on Sunday.
The four days of exercises include the USS George Washington aircraft carrier and its battle group.
North Korea's official KCNA news agency said: "If the US brings its carrier to the West Sea of Korea (Yellow Sea), no-one can predict the ensuing consequences."
The BBC's Chris Hogg in Seoul says that, coming just a few hours before the military exercises, the latest warnings and threats from North Korea are certain to anger the South further.
In Seoul on Saturday, about 1,000 South Korean military veterans protested at the deaths, burning the North Korean flag and portraits of Pyongyang's leaders. The protesters shouted slogans demanding revenge and condemning the North's "atrocity".
KCNA said Seoul was using the civilian casualties for propaganda, in its words "creating the impression that the defenceless civilians were exposed to indiscriminate shelling from the North".
Pyongyang said it had been provoked by the South's military exercises, which were being carried out close to Yeonpyeong.
It said the North had sent a "telephone notice" on the morning of the shelling "to prevent the clash at the last moment" but the South continued its "provocation".
South Korea says two men in their 60s, who were working on the island, were killed by the shells.
The funeral service for the two marines who died, Seo Jeong-woo and Moon Kwang-wook, was held at a military hospital in Seongnam, close to Seoul, on Saturday and was broadcast on television nationwide.
Hundreds of government and military officials, politicians, religious leaders, activists and civilians attended. Among them were Prime Minister Kim Hwang-sik .
Officials and relatives placed white flowers on the two coffins draped in the South Korean flag. Marines sang as the coffins were carried out.
Maj Gen You Nak-jun, the head of the marine corps, said: "We'll certainly repay North Korea a thousand-fold for killing and harming our marines.
"South Korean active-duty marines and all reserve forces will engrave this anger and hostility in our bones and we will make sure we take revenge on North Korea."
South Korea's new Defence Minister Kim Kwan-jin said that tougher action was needed against the North.
"We need to deal with North Korea's provocations strongly. We need to hit back multiple times as hard."
The US says Sunday's joint military drills are defensive, but are designed to deter the North from carrying out further attacks.
The North calls the military drills an "unpardonable provocation". State media promised a "sea of fire" if North Korean territory was violated.
China said the drills would escalate tension and warned against any infractions into its exclusive economic zone, which extends 320km (200 miles) from its coast.
The US has called on China to increase its pressure on Pyongyang to prevent further incidents.
China has said its "top priority" is to keep the situation under control. Beijing has begun a series of talks in an attempt to ease the tension.
On Friday, China's Foreign Minister Yang Jiechi met the North's ambassador in person, and spoke on the phone to his US and South Korean counterparts, according to the state-run Xinhua news agency.
However, the top US military commander, Adm Mike Mullen, said he did not know "why China doesn't push harder" with Pyongyang.
In an interview with CNN due to be broadcast on Sunday but released as a transcript, Adm Mullen said Beijing appeared to mistakenly believe it could control North Korea's leader, Kim Jong-il.
"I'm not sure he is controllable," Adm Mullen said.
South Korea has increased its troop numbers on Yeonpyeong and says it will change its rules of engagement to allow it to respond more forcefully if incidents such as Tuesday's happen again.
This week's tension comes as the North is undergoing an apparent transition of power from Kim Jong-il to his young son Kim Jong-un.