Il Nuovo Postiglione - Second group of prisoners transferred to El Salvador mega-jail

"In a new operation we transferred the second group of 2,000 gangsters to the Center for the Confinement of Terrorism (CECOT)," Bukele said on Twitter.

The president published a video of heavily tattooed barefoot men in white shorts with their heads bowed and hands cuffed behind their backs being hurriedly moved around and loaded onto buses.

Bukele has boasted that the new facility is the largest mega-prison in the Americas, but rights groups have criticized it over its severe conditions.

Defense Minister Rene Francis Marino said 1,200 soldiers took part in the security operation that began at dawn and included three Air Force helicopters.

The first 2,000 inmates were moved last month.

The prison was built to accommodate some of the 65,000 suspected gangsters detained as part of the war on crime launched last year by Bukele, who ordered a state of emergency a year ago, allowing arrests without warrants in the violence-plagued country.

The transfer operation took place on the same day that Justice and Security Minister Gustavo Villatoro asked parliament to extend the state of emergency for another month.

The prison in Tecoluca, 74 kilometers (46 miles) southeast of the capital San Salvador, is built from reinforced concrete and made up of 32 cells of about 100 square meters (1,075 square feet), designed to hold more than 100 inmates.

Each cell has only two sinks and two toilets, with 80 metal bunks for every 100 prisoners and no mattresses.

Rights groups have criticized the construction as a violation of incarceration standards.

C.Albano--INP