SEOUL, South Korea — South Korea is ready to deter any retaliation by North Korea following the two countries' first naval clash in seven years, officials said today, as the top U.S. diplomat said the skirmish will not scuttle a planned visit to Pyongyang by an American envoy.

Tuesday's clash occurred hours before U.S. officials said President Barack Obama had decided to accept a North Korean invitation to send the envoy to Pyongyang for the first direct talks during his administration. The exchange of fire sparked speculation that the North was trying to foment tensions to gain a negotiating advantage.

The naval clash "does not in any way affect our decision" to send envoy Stephen Bosworth to Pyongyang, U.S. Secretary of State Hillary Rodham Clinton said in Singapore today. "We think it is an important step that stands on its own."

Bosworth's trip is aimed at persuading communist North Korea to return to six-nation nuclear disarmament negotiations. North Korea walked away from those talks earlier this year.

Both sides blamed the other for Tuesday's two-minute clash in a rich crab-fishing area off the countries' west coast, where both sides regularly accuse the other of violating the disputed border.

South Korean officials said the North Korean ship was on fire and heavily damaged when it retreated. The South Korean ship was lightly damaged and there were no South Korean causalities, according to the Joint Chiefs of Staff.

South Korea's mass-circulation Chosun Ilbo newspaper and other media reported that one North Korean officer was believed killed and three other sailors wounded.

Defense Minister Kim Tae-young told the National Assembly on Tuesday that he believed the North may take retaliatory actions, saying President Lee Myung-bak "also has such concerns."