Biden visits US-Mexico border amid crisis

President Joe Biden visited the US-Mexico border for the first time since taking office, tackling one of the most politically charged issues in the country as he prepares for a re-election bid.

Accompanied by Border Patrol agents on Sunday, Biden toured a section of the wall that divides the two countries, a signature priority of his Republican predecessor Donald Trump, in an effort to demonstrate that he was taking the issue seriously.

Biden on Thursday said his administration would tighten immigration enforcement by blocking Cuban, Haitian and Nicaraguan migrants at the border, expanding the nationalities of those who can be expelled back to Mexico.

But that has not impressed Republicans like Texas Governor Greg Abbott, who accused him of failing to enforce immigration laws.

"You have violated your constitutional obligation to defend the States against invasion through faithful execution of federal laws," Abbott, a possible 2024 presidential candidate, wrote in a letter he handed to Biden upon his arrival in the state.

Biden told reporters he had not yet read the letter.

Joined by Secretary of Homeland Security Alejandro Mayorkas, the president also visited the Bridge of the Americas, which connects the United States and Mexico, and viewed equipment that border officials use to detect illegal drugs.

Biden hopes to strengthen relations with Border Patrol agents, some of whom have bristled at the rollback of hardline enforcement policies by the White House.

The long-term goal of Congress reforming America's creaky immigration system is unlikely to succeed given Republicans' newly assumed control of the US House of Representatives.

Right-wing politicians have repeatedly torpedoed US immigration reform proposals over the past two decades.

Biden sent Congress an immigration reform plan on his first day in office two years ago, but it floundered due to opposition from Republicans, who also blocked his request for $US3.5 billion to beef up border enforcement.

Republicans are pushing their own plans for the border after securing a narrow majority in the House of Representatives in the 2022 midterm elections.

El Paso's Democratic mayor declared a state of emergency last month, citing hundreds of migrants' sleeping on the streets in cold temperatures and thousands being apprehended every day.

US border officials apprehended a record 2.2 million migrants at the border with Mexico in the 2022 fiscal year that ended in September, though that number includes individuals who tried to cross multiple times.

At the same time as he expanded his authority to expel migrants, Biden on Thursday opened legal, limited pathways into the country for Cubans, Nicaraguans and Haitians - allowing up to 30,000 people from those three countries plus Venezuela to enter the country by air each month.

While winning praise from some US industry groups desperate to solve pressing labour shortages, Biden's moves have drawn criticism from human rights activists and some Democrats who say the new restrictions are a retreat from the president's 2020 campaign promise to restore historical rights to asylum-seekers.

After the El Paso visit, Biden took Air Force One south to an airport near Mexico City, where he was greeted by Mexican President Andres Manuel Lopez Obrador.

Biden, Lopez Obrador and Canadian Prime Minister Justin Trudeau will hold a three day summit beginning on Monday on energy, economic co-operation, immigration and drug trafficking, especially fentanyl.