International donors have pledged an additional $580 million in assistance for earthquake relief efforts in Pakistan.

Top United Nations relief official Jan Egeland said the pledges came at a donor meeting in Geneva. But officials said it was not clear how much money was intended for emergency relief aid, and how much was for long-term reconstruction efforts.

Earlier, U.N. Secretary-General Kofi Annan appealed for help to prevent a second wave of deaths. Officials have warned that thousands of people may die if they do not receive aid before key supply routes are blocked by winter snow and freezing temperatures.

The United States has pledged $156 million for humanitarian aid, reconstruction and relief operations by American military personnel.

The death toll in Pakistan now stands at more than 54,000 people, and officials say rebuilding damaged areas will cost $5 billion.