MARRAKESH, Morocco - Hopes dimmed on Tuesday in Morocco's search for survivors, four days after a powerful earthquake killed more than 2,800 people, most of them in remote villages of the High Atlas Mountains.

Search-and-rescue teams from the kingdom and from abroad kept digging through the rubble of broken mud-brick homes, hoping for signs of life in a race against time following the 6.8-magnitude quake late Friday.

The Red Cross appealed for more than $100 million in aid to meet the "most pressing needs", including water, shelter, health and sanitation services.

"We need to make sure we avoid a second wave of disaster," said Caroline Holt, global director of operations at the International Federation of Red Cross and Red Crescent Societies.

In the tourist hub of Marrakesh, whose UNESCO-listed historic centre suffered cracks and other major damage, many families still slept out in the open, huddled in blankets on public squares for fear of aftershocks.

But the need was most desperate in remote and poor mountain villages, many only reachable via winding dirt roads, where traditional adobe homes crumbled to rubble and dust and inhabitants have searched by hand for missing relatives.

Dozens of quake survivors crowded around the open back doors of a truck in Amizmiz waiting for the packages of food aid being handed out by volunteers on Tuesday.

"We have nothing. We lost everything. We're here just to get some food to eat," said 39-year-old Fatima Benhamoud, who received a box with beans, canned food and crackers.

Her home in Azmizmiz collapsed in the quake and her children barely managed to escape with their lives.

"But what are we going to do when people stop helping us?" she asked.

- Remote villages destroyed -

Rescuers, aid trucks and private volunteers kept travelling to stricken villages in the barren foothills of the High Atlas, many accessible only via dusty dirt roads affected by rockfalls.

In the village of Asni, in the worst-hit province of Al-Haouz, the army set up a field hospital with medical tents where more than 300 patients had been treated by Monday, Colonel Youssef Qamouss told AFP.

"The hospital was deployed 48 hours ago," he said, adding that it has an X-ray unit, pharmacy and other facilities. "It started operating this morning and we're already at more or less 300 patients."

Many Moroccan citizens have rushed to help quake victims with food, water, blankets and other aid or by donating blood to help treat the injured, an effort joined by the national football team.

The quake was Morocco's strongest on record and the deadliest to hit the North African country since a 1960 earthquake destroyed Agadir on the Atlantic coast, killing between 12,000 and 15,000 people.

Overall, at least 2,862 people have died and more than 2,500 been injured in the latest tragedy, according to an official toll issued late Monday.

Morocco has allowed rescue teams to come to its aid from Spain, Britain, Qatar and the United Arab Emirates but so far declined offers from several other nations, including the United States and Israel.

- 100,000 children affected -

Albert Vasquez, the Spanish unit's communications officer, warned on Monday that "it's very difficult to find people alive after three days" but stressed that "hope is still there".

The United Nations estimated that more than 300,000 people have been affected, one third of them children, by the powerful seismic event that hit just after 11:00 pm (2200 GMT) when most families were asleep.

"Thousands of homes have been destroyed, displacing families and exposing them to the elements at a time of year when temperatures drop down during the nighttime," the UN children's agency said.

"Schools, hospitals and other medical and educational facilities have been damaged or destroyed by the quakes, further impacting children."

The rebuilding effort is expected to be enormous for the country which is already suffering economic woes and years of drought and now fears a downturn in the crucial tourism sector.

Prime Minister Aziz Akhannouch chaired a Monday meeting on housing and reconstruction and then pledged that "citizens who have lost their homes will receive compensation," adding that the details would be announced later.