WASHINGTON, STATE DEPARTMENT - Hundreds of millions of dollars in emergency aid and rescue workers from all over the world are pouring into Ecuador as the death toll from Saturday's powerful earthquake climbed past 500.
That number is likely to grow, with officials saying more than 200 people are missing.
Rescuers and citizens along the Pacific coast are using everything from heavy equipment and dogs to their bare hands to dig through the collapsed homes and stores, straining to listen for cries of help.
A number of survivors have been pulled out of the rubble, but authorities say the cellphone calls and text messages from people buried under the wreckage are fading.
"Let's not kid ourselves," President Rafael Correa said after visiting the damage Tuesday. "It will be a long struggle ... reconstruction for years, billions [of dollars] in investment."
Ecuador's economy is already in a severe recession because of dropping oil prices.
President Barack Obama telephoned Correa on Tuesday to convey the condolences of the American people for the earthquake deaths. He assured Correa that the U.S. will do all it can to help Ecuador recover.
Saturday's 7.8 magnitude quake was felt across the entire country, but the coastal cities of Portoviejo, Manta and Pedernales were hit the hardest.
The government says it will draw down on $600 million in credit from several multinational lenders, including the World Bank, to finance its emergency response efforts. The economy of the small South American member of OPEC is mired in recession because of plunging prices on the global oil market.
The U.S. Agency for International Development announced Tuesday that it will deploy two teams to the site — one to assist the government by assessing damage and needs, and a second to work with a U.N. team to coordinate international rescue activities. USAID has also pledged an initial contribution of $100,000 for critical supplies.
Worst natural disaster
The quake, Ecuador's worst natural disaster in more than half a century, injured more than 2,500 people and left thousands homeless. The death toll includes three Cuban doctors, a Catholic missionary nun from Northern Ireland, two Canadians and one U.S. national.
UNICEF reported Tuesday that the quake has affected at least 150,000 children, having damaged 119 schools.
"We are in a race against time to protect children from disease and other risks common in such emergencies," said UNICEF's representative in Ecuador, Grant Leaity.
Search-and-rescue crews have launched a desperate effort to find survivors trapped in the rubble of buildings destroyed in the quake. Three people were pulled out alive from the rubble of a shopping center in Manta after being trapped for 32 hours.
Thousands of soldiers and police have been deployed throughout Ecuador to provide emergency relief, including temporary shelters and food. In addition, scores of aid workers from dozens of nations, including Spain, Peru, Cuba, Bolivia and Venezuela, have arrived to assist in the relief efforts, and the United Nations said it is preparing to airlift tons of emergency supplies.
VOA's Kenneth Schwartz contributed to this report.
WATCH: Video footage from Ecuador