US authorities on Sunday plan to fly thousands of migrants hiding under a bridge in Texas back to where they started their journey.

These are mainly migrants from Haiti.

In recent weeks, the border town of Del Rio has had to deal with a large increase in migrants.

What exactly is going on?

More than ten thousand migrants are camped under the bridge that connects the border town of Del Rio in Texas with the Mexican city of Ciudad Acuña.

Among them are mainly Haitians, but also people from Cuba, Peru, Venezuela and Nicaragua.

Local authorities are struggling to provide food and drink to the large number of people.

Moreover, during the day it is about 37 degrees Celsius and the sanitary facilities are poor.

On Friday, about 2,000 people were taken away and transferred to shelters.

The US government has indicated that it plans to fly the migrants back home.

The first deportation flights are expected to take place on Sunday.

Four hundred additional observers have also been sent to Del Rio.

Why is the number of migrants from Haiti towards the US increasing?

Last month, Haiti was hit by a massive earthquake that killed more than 2,000 people.

At least 12,000 people were injured and many homes, hospitals and schools were destroyed or damaged.

Then Tropical Storm Grace passed over the area.

In July, President Jovenel Moise was assassinated.

On Tuesday, Haiti's Prime Minister, Ariel Henry, was identified by prosecutors as suspected of involvement in the president's assassination.

Shortly after the news came out, that same prosecutor was fired by Henry.

The political situation in Haiti is unsettled by the assassination attempt.

Several human rights groups have criticized the plan to return Haitians.

Why this puts political pressure on Biden:

The US president had promised to adopt a more humanitarian immigration policy than his predecessor Donald Trump.

For example, he promised to pave the way to American citizenship for millions of undocumented immigrants.

But Biden has had to take tough measures to deal with the number of migrants crossing the border.

According to some Republicans, Biden's more tolerant policies are at the root of the current border crisis.

Texas Republican Senator John Cornyn wrote on Twitter: "The Biden administration is in complete disarray and is handling this border crisis as badly as the evacuation from Afghanistan."