500 children reunited with families at US border after days of separation

However, the official did not know how many of the 500 children were being held with their parents and how many had been deported from the US.

He added that officials are working to establish a centralized reunification process for the remaining detained children and their families at the Port Isabel Detention Center near Los Fresnos, Texas.

In May, US Attorney General Jeff Sessions announced a "zero tolerance" policy for illegal immigrants, which stipulates that people arrested for illegal immigration into the US, including refugees, will be taken directly to federal court while their children will be referred to the Office of Refugee Resettlement and Human Services.

This policy has sparked a wave of strong protests in the US. According to statistics from the US Department of Homeland Security, about 2,000 immigrant children were separated from their parents over a period of more than 6 weeks, from April 19 to May 31 under this new immigration policy.

Public pressure is believed to have prompted President Trump to sign an executive order allowing families who illegally cross the border from Mexico into the US to stay together while immigration regulations are reviewed.

However, the US leader said he would not change his "zero tolerance policy" of prosecuting cases of intentionally illegally crossing the border into the US.