Foreign ministers are gathering in the Swiss city of Geneva, where discussions are expected to be dominated by the violent turmoil in Libya.
United States Secretary of State Hillary Clinton says she will discus co-ordinated responses with her counterparts from Europe, the Middle East and North Africa.
Earlier Libyan leader Muammar Gaddafi dismissed new United Nation sanctions against him, saying a small group of rebels protesting against his rule are surrounded and will be defeated.
In a telephone interview with Serbian television, he said the UN Security Council vote imposing travel and asset sanctions on him and close aides was null and void. He said the people of Libya still support him.
British Foreign Secretary William Hague says Gaddafi should step down.
"It is the best hope for Libya," Mr Hague said.
The US and Switzerland have already announced they are freezing the Libyan leader's holdings.
The UN Security Council unanimously approved sanctions against the Gaddafi regime for its use of violence by security forces against protesting civilians.
The council agreed to impose an arms embargo on Libya, freeze the assets of the Gaddafi family and refer the Libyan authorities to the International Criminal Court.