Nearly 70 illegal migrant workers, mostly Ethiopians, have fled from a detention centre in the Saudi capital, local media reported Friday, adding that authorities have rearrested 25 of them.
Police have been cracking down on illegal migrants since the expiration in November of a seven-month amnesty during which they had to regularise their status or leave the country, in operations that have sparked deadly clashes.
"Around 70 detainees broke the wall of their cell at a foreigners' detention centre in Al-Marbaa neighbourhood of Riyadh and managed to escape," online news website Sabq.org said, quoting a prisons spokesman, Abdullah al-Harbi.
"Twenty-five of them have been caught and a search is ongoing for the rest," he said.
Al-Hayat daily reported that the inmates dug a hole into the wall of their cell and escaped early on Thursday.
Nearly one million foreign migrants took advantage of last year's amnesty to leave voluntarily, while another four million were able to find employers to sponsor them, a legal requirement in Saudi Arabia and other Gulf states.
Since the start of this year, Saudi authorities have deported nearly 574,000 illegals, according to official figures.
More than 13,000 migrants are still being held at detention centres across the kingdom awaiting completion of their deportation procedures.
In March, one illegal migrant died and nine others were wounded when police intervened to quell "chaos" at Al-Shumaisi detention centre in western Saudi Arabia, police said.
Expatriates account for nine million of the oil-rich kingdom's population of 27 million.
Despite its huge oil wealth, Saudi Arabia has a jobless rate of more than 12.5 percent among its citizens, a figure the government has struggled to bring down.