Guatemala's disaster response agency on Tuesday raised the number of missing persons to 577 from 384, while the toll remained at 652.
Another 133 people have died in El Salvador, Mexico, Costa Rica, Nicaragua and Honduras due to the heavy rains, which were partly spawned by Hurricane Stan.
Also on Tuesday, President Oscar Berger and Nobel Peace Prize winner Rigoberta Menchu arrived in Guatemala by helicopter to the cheers and hugs of hundreds of people who swarmed Santiago Atitlan's town square, a stone courtyard fronting a 17th-century church.
"We came to share the pain of all the people who lost loved ones," Berger said, after giving a bear hug to Santiago Atitlan mayor Diego Esquina.
"We are very worried about Santiago Atitlan, [but] I have the impression that we have never been as united."
Later, he hiked through the mudslide that buried Panabaj, where he said the final toll - together with another nearby hamlet - would reach 400.
He said Panabaj would be abandoned forever, and land would be provided for villagers to relocate elsewhere.
Symbol of hope
He declared the area a "symbol of national reconstruction" and said trucks were bringing in tin roofing to build temporary shelters.
He also urged tourists to return to the lake, an area popular with foreigners, to help bring the area back to life.
Menchu called on local communities to preserve their culture and traditions, despite the loss of life and likely relocation. She also asked other Mayan communities to donate traditional clothing.
"We came to share the pain of all the people who lost loved ones. We are very worried about Santiago Atitlan, [but] I have the impression that we have never been as united"
"Lake Atitlan is a mirror for many Mayan villages," she said.
Officials in Santiago Atitlan, on the shores of Lake Atitlan about 140km west of the capital, Guatemala City, set up a 100-metre perimeter around the massive mudslide that buried the nearby community of Panabaj.
"We don't want epidemics," Esquina said, adding that "it is no longer possible" to recover any more bodies from the site.
The cadavers were decomposing rapidly and the hillside under which they lay was still highly unstable, making rescue efforts too risky, Esquina said.
Berger later declared the area a high-risk zone.
Some 107,000 Guatemalans were staying in shelters after their homes were either damaged or destroyed in the natural disaster.
In addition, there were several scattered communities that still remained blocked from outside help,
Guatemalan Agriculture Minister Alvaro Aguilar said that the government had stored up about two months' worth of food for emergencies, but used an entire month's supply just last week.
He estimated that the country would need at least 20,000 tonnes of food during the next three months.
More aid needed
The government on Monday night issued an urgent call to the United Nations seeking $21.5 million in aid because its own emergency response funds would not be enough to cope with the crisis.
Several countries already have offered to provide assistance to Guatemala, including flood-stricken Mexico.
Some 107,000 Guatemalans have
been made homeless
Sweden has donated $5 million and other governments, including Spain, France, and Taiwan, have sent aid shipments.
The United Nations Children's Fund announced on Tuesday that more than one-third of the victims were children and that it was rushing emergency relief supplies to communities both in Central America and Mexico.
Unicef said it was seeking close to $6 million for Guatemala and El Salvador alone "and has already diverted hundreds of thousands of dollars from its regular development programmes in the affected countries to help governments and non-governmental organisations respond to the crisis".
US helicopters shuttled food and water to isolated villages, and additional aid was on the way to both Guatemala and El Salvador, where 71 people died in deadly flooding and landslides, said Roger Pardo-Maurer, the deputy assistant secretary of defence for the US government's Western Hemisphere policy.
A medical unit from the Arkansas National Guard also was preparing to go.
Pardo-Maurer said the US was sending food, water, plastic sheeting, medical supplies and other equipment and would be helping to improve communications.