Police in Saudi Arabia have arrested at least 400 mostly African illegal migrants south of the capital Riyadh, local media reported on Friday.
The authorities 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 kingdom.
Some operations in the crackdown have sparked deadly clashes.
The Arab News reported that "more than 400 undocumented expatriates, including women and children living in the Manfuha district (of Riyadh)... were rounded up during operations" early on Thursday.
The daily quoted a police official in the capital as saying that the migrants were arrested for "various offences, such as overstaying their visas, running away from sponsors and looking for employment".
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They will be subject to fines and deportation depending on each case, the Arab News quoted police sources as saying.
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.
The Saudi authorities have deported nearly 574,000 illegals this year, official figures show.
More than 13,000 migrants are still being held at detention centres across the country awaiting completion of their deportation procedures.
Expatriates account for nine million of the oil-rich desert 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 own citizens, a figure the government has struggled to reduce.