DEMOCRATIC US presidential candidate Beto O’Rourke has declared that immigrants make the country safer, as he staged rallies across Texas to formally kick off his 2020 White House bid.

The former congressman, who represented El Paso for three terms until last year, addressed 1000-plus supporters in his hometown of El Paso across the border from Ciudad Juarez, Mexico.

O’Rourke declared: “We are safe, not despite the fact that we are a city of immigrants and asylum seekers. We are safe because we are a city of immigrants and asylum seekers.”

“We have learned not to fear our differences, but to respect and embrace them,” he told a crowd that waved small American flags and black-and-white signs reading Viva Beto.

In a series of tweets on Friday, President Donald Trump warned he could close the US southern border next week “if Mexico doesn’t immediately stop ALL illegal immigration coming into the United States”.

But O’Rourke has made promoting the border as economically powerful the centrepiece of his campaign.

He has also vowed to legalise marijuana, defend abortion rights, strengthen unions and bring home troops from Iraq and Afghanistan.

He also renewed his support for a House proposal called Medicare for America, which he says will guarantee people universal health care coverage.

He decried federal officials’ recent decisions to hold people who crossed into the US to seek asylum “in cages” under El Paso’s international bridges, saying those detainees “are our fellow human beings and deserve to be treated as our fellow human beings”.

O’Rourke entered the race on March 14 and has already visited nine states.