US Defence Secretary Robert Gates on Sunday said any efforts to make North Korea accountable over the sinking of a South Korean warship may have little effect given Pyongyang's defiant attitude, DPA reported.
North Korea's stance was an obstacle for finding the adequate measures short of military options, Gates told the BBC on the sidelines of a summit on Asian security in Singapore.
"You can bring together additional pressure, you can do another resolution at the UN," Gates said in an interview posted on the BBC website.
"As long as the regime doesn't care about what the outside world thinks of it, as long as it doesn't care about the well-being of its people, there is not a lot you can do about it, to be quite frank, unless you are willing at some point to use military force," he said.
"And nobody wants to do that," Gates said.
His remarks came after South Korea filed a complaint to the United Nations Security Council accusing the North of sinking its vessel Cheonan on March 26, causing the deaths of 46 sailors.
On Saturday, Gates told defence ministers and policymakers at the 2010 Shangri-La Dialogue in Singapore that the US was reviewing additional options to deal with North Korea, but did not elaborate.
"To do nothing would set the wrong precedent," he said, calling on the international community to hold North Korea accountable for the Cheonan sinking.
An multinational investigation concluded that a torpedo from the North likely sank the ship, but Pyongyang denied any involvement and threatened war against the South if any punitive measures are taken.