Haitian migrants receive drinks at a shelter in Ciudad Acuna, Coahuila state, Mexico, on Tuesday. Mexico has told the US that it wants a regional agreement to tackle the tide of migrants arriving at the two countries' borders, Foreign Minister Marcelo Ebrard said on Tuesday. Photo: VCG

The United Nations expressed deep concern Tuesday at mass deportations of Haitian migrants from the US, warning they could go against international law.

The White House has faced a torrent of criticism after the US started sending planeloads full of Haitian nationals back to their crisis-wracked country over the weekend.

The crisis intensified after pictures by AFP photographer Paul Ratje that spread quickly over social media appeared to show riders swinging their reins to threaten migrants and push them back toward the Rio Grande river.

The head of the UN refugee agency UNHCR, Filippo Grandi, said he was "shocked by images of the deplorable conditions beneath the concrete highway overpass in Del Rio, Texas, where more than 14,000 Haitians had gathered after arduous journeys."

He also lashed out at the US government's Title 42 policy, which was brought in by the previous administration of Donald Trump to stop most arrivals at the southern border on the grounds that migrants could spread COVID-19.

"The summary, mass expulsions of individuals currently under way under the Title 42 authority, without screening for protection needs, is inconsistent with international norms and may constitute refoulement," Grandi said in a statement. "Refoulement" - returning asylum seekers to places where they risk persecution and threats to their life - is illegal under international law.

Earlier in the day, the UN human rights and refugee agencies joined up to criticize the deportations.

"We are seriously concerned by the fact that it appears that there has not been any individual assessment in the [Haiti] cases," human rights office spokeswoman Marta Hurtado told reporters in Geneva.

This, she said, indicated that "maybe some of these people have not received the protection that they needed."

UNHCR spokeswoman Shabia Mantoo stressed that seeking asylum is "a fundamental human right." "We are calling for this right to be respected."

The deportation of Haitian migrants had been temporarily suspended by Washington after a devastating earthquake hit the Caribbean nation in August.

The UNHCR hailed the administration of President Joe Biden for its announcement that it will double the number of refugees it will accept in the next fiscal year to 125,000.