At least 1,419 people are known to have died in the 7.2-magnitude quake. More than 6,900 were injured, and an unknown number are still missing.

Tropical Depression Grace is expected to dump up to 25cm (10 inches) of rainfall over the worst affected area.

It is feared the deluge could trigger landslides.

Social media footage showed heavy rain pouring over the island’s east, with the quake-hit west next in its path.

Roads already made impassable by the quake could be further damaged by the rains, so aid teams are racing to get essential provisions to the quake-hit region.

On Twitter, Haiti’s civil protection agency urged “good neighbours whose space has not been affected” to help shelter displaced people.

Search and rescue teams have been arriving from the United States and Chile, with more on the way from Mexico. Cuban medical teams are already in Haiti and helping people.

Humanitarian organisations say survivors need drinking water and shelter. More than 30,000 families have reportedly been left homeless.

Homes, churches and schools were among buildings flattened in the quake. Some hospitals were left overwhelmed and in need of supplies as they struggled to treat the injured.

The earthquake compounds problems facing the impoverished nation, which is already reeling from a political crisis following the assassination of its president last month.

The south-west of Haiti appears to have suffered the worst of the damage, especially around the city of Les Cayes.

Footage on social media showed residents desperately trying to pull victims from ruined buildings.

“The streets are filled with screaming,” Archdeacon Abiade Lozama, head of an Anglican church in Les Cayes, told the New York Times. “People are searching, for loved ones or resources, medical help, water.”

The epicentre of Saturday’s quake was about 12km (7.5 miles) from the town of Saint-Louis du Sud, the US Geological Survey (USGS) said.

But the tremor could be felt in the densely-populated capital of Port-au-Prince, some 125km away, and in neighbouring countries.

By James Clayton, BBC News, Les Cayes

It’s hard enough to treat survivors of any natural disaster but when the hospitals themselves are under fear of collapse it makes it all the more difficult.

Les Cayes Ofatma hospital is deemed too unsafe so they’ve brought everyone outside. People swat away flies on hospital beds placed under makeshift tents and trees. You can hear people screaming in pain.

One woman, Elsy, had only just woken up when the earthquake happened. Her son has a serious fracture to his leg.

There simply aren’t the facilities needed to treat people in this remote part of the country. One doctor comes to us, angry, asking why he has no medicine.

One woman we spoke to – who has a very bad broken leg and is also pregnant – has had no pain relief for two days.

The people here need help, but at the moment not enough help is coming – and with a tropical storm close by it could become even more difficult.

Prime Minister Ariel Henry declared a month-long state of emergency and urged the population to “show solidarity”.

The Pope offered prayers for the victims during a Sunday address and expressed hope that aid would arrive soon.

Japanese tennis star Naomi Osaka, whose father is from Haiti, said she would donate her earnings from next week’s Western & Southern Open to help finance relief efforts.

Aftershocks were felt after the initial tremor on Saturday, with the USGS initially warning the earthquake could result in thousands of fatalities and injuries.

A 2010 earthquake in Haiti killed more than 200,000 people and caused extensive damage to the country’s infrastructure and economy.

“How many more American lives is it worth?” asked the Democratic president.

He said that despite the “messy” pullout, “there was never a good time to withdraw US forces”.

On Sunday, the Taliban declared victory after Afghan President Ashraf Ghani fled and his government collapsed.

The militants’ return to rule brings an end to almost 20 years of a US-led coalition’s presence in the country.

Kabul was the last major city in Afghanistan to fall to a Taliban offensive that began months ago but accelerated in recent days as they gained control of territories, shocking many observers.

Mr Biden’s address followed a dramatic day at Kabul’s international airport, where hundreds of civilians desperate to flee the country forced their way inside on Monday.

Many thronged the runway, running alongside a moving military transporter aircraft as it prepared for take-off.

Some clung to the side of plane, and at least two of them are reported to have perished when they fell from the aircraft after it had left the ground.

American troops killed two armed Afghans who were part of the crowd that breached the airport perimeter. Seven people reportedly died in total.

The US suspended its evacuation from Kabul but it has now resumed.

A remarkable picture from Sunday appears to show 640 Afghans packed onboard a US military cargo plane leaving Kabul for Qatar.

The image, not verified by the BBC, was obtained by the US defence analysis website, Defense One.

Panicked civilians had scrambled up the loading ramp, the website quoted US officials as saying, but the crew decided it was best to take off rather than force the Afghans off. The number onboard could be a record for that type of plane – a C-17 Globemaster.

In a separate development, the Taliban have announced what they are calling a general amnesty for government officials, and have urged them to return to work.

A statement said officials should “continue their duties without any fear”.

Mr Biden returned on Monday to the White House from the Camp David presidential retreat to make his first public remarks on Afghanistan in nearly a week.

“If anything, the developments of the past week reinforce that ending US military involvement in Afghanistan now was the right decision,” said Mr Biden.

“American troops cannot and should not be fighting in a war and dying in a war that Afghan forces are not willing to fight for themselves.”

Mr Biden is facing an intense political backlash over the turmoil in Kabul following his April decision to order all American troops out of Afghanistan by 11 September – the 20 year anniversary of the terror attacks that triggered the US invasion.

Mitch McConnell, Republican Senate Minority Leader, tweeted: “What we are seeing in Afghanistan is an unmitigated disaster. The Biden Administration’s retreat will leave a stain on the reputation of the United States.”

Former US President George W Bush, who authorised the military intervention in 2001, said he was “watching the tragic events unfolding in Afghanistan with deep sadness”.

“The Afghans now at greatest risk are the same ones who have been on the forefront of progress inside their nation,” Mr Bush said, stressing that the US had “the legal authority to cut the red tape for refugees during urgent humanitarian crises”.

In his speech, Mr Biden said the US mission in Afghanistan was never supposed to have been about nation-building.

He said that when he was vice-president he had opposed the 2009 deployment of thousands more troops into the country by former President Barack Obama.

Mr Biden also noted he had inherited a deal negotiated with the Taliban under former President Donald Trump for the US to withdraw from Afghanistan by May of this year.

He said he was now the fourth US president to preside over America’s longest war, and would not pass the responsibility on to a fifth.

“I will not mislead the American people by claiming that just a little more time in Afghanistan will make all the difference.”

Mr Biden campaigned as a seasoned expert in foreign policy and declared after assuming office this year that “America is back”.

Last month he assured reporters it was “highly unlikely” the Taliban would overrun the entire country.

But he conceded on Monday that “this did unfold more quickly than we had anticipated”.

Opinion polls suggest most Americans support the US exiting Afghanistan.

But Mr Biden is facing a barrage of criticism over the manner of the departure, after he withdrew US troops then sent thousands back in to help the evacuation.

Images emerged on Sunday showing US helicopters circling the US embassy in Kabul.

For many, the pictures evoked America’s humiliating departure from Saigon, Vietnam, in 1975 when Mr Biden was a junior senator.