South Korean authorities Friday rejected North Korea’s demand to send back nine refugees from the communist state.

South Korean authorities Friday rejected North Korea's demand to send back nine refugees from the communist state, an issue that could further chill frosty relations.

"As all nine North Koreans wish to defect, according to the investigation by relevant agencies, it will be handled in accordance with their free will," the South's Red Cross said in a message to its North Korean counterpart.

The message was relayed in a statement from South Korea's unification ministry.

The three men, two women and four children crossed the Yellow Sea border last Saturday in two small boats. They have said they want to stay in the South, according to Seoul officials.

The North's Red Cross warned Thursday that relations could be further damaged unless the South immediately sends them back.

But Seoul's policy is to accept all North Koreans who wish to stay in the South, while repatriating those who stray across the sea border by accident.

The arrival in February of a boatload of North Koreans sparked weeks of acrimony. That boat drifted across the Yellow Sea border in thick fog, possibly accidentally.

North Korea attacking South Korea - SK Marines killed, many injured, countless houses ablaze; Nov 2011.

Seoul returned 27 of the 31 people on board but refused to hand over the other four, saying they had freely chosen to stay in the South.

Pyongyang complained bitterly that the four had been pressured to stay and publicized appeals from their relatives for them to come home.

The latest incident comes at a time of high cross-border tensions, after the North announced late last month it was breaking all contacts with the South's government.

The North's military has threatened an attack in protest at the use, by some South Korean troops, of photos of Pyongyang's ruling family as rifle-range targets. The practice has been stopped but the North is demanding an apology.

However, one analyst has said the latest defection will not seriously aggravate the situation.

"The North cannot help but demand their return, as usual, but it will have to swallow (the situation) as the nine came to the South of their free will," said Kim Yong-Hyun, of Seoul's Dongguk University, on Thursday.

The nine are being questioned by police and military and intelligence officials to verify they are genuine refugees and not spies seeking cover to slip into the South.

Some 21,000 North Koreans have fled to the capitalist South since the end of the 1950-1953 war, the vast majority in recent years, to escape repression or poverty and food shortages.