Story highlights A Sudanese national was killed and 17 injured Wednesday in the Saudi capital of Riyadh

Two people were killed and 561 arrested Saturday in clashes between police and foreign workers

Saudi Arabia launched a "security campaign" this month to crack down on visa violations

A Sudanese national was killed and 17 others injured in the Saudi capital during ongoing clashes over a visa crackdown, the Saudi Press Agency reported.

The death Wednesday came after two people were killed and 68 others injured Saturday in clashes between police and foreign workers, the Saudi Press Agency said.

Saudi authorities began rounding up thousands of illegal foreign workers last week after the expiration of an amnesty to formalize their status.

The crackdown is mainly concentrated in Manfouha, a district of the capital city, Riyadh.

In light of Saturday's clashes, a police spokesman urged workers without proper documents to surrender at a shelter in Riyadh until they could be deported.

Most of the workers impacted by recent police raids are African migrants. Reports circulated last week of the death of an Ethiopian man, prompting the Ethiopian Foreign Ministry to issue a statement that it "condemned the killing of an Ethiopian and mistreatment of its citizens residing in Saudi Arabia."

Saudi Arabia launched a "security campaign" this month to crack down on workers violating visa rules.

Khaled Al Maeena, editor-in-chief of the Saudi Gazette, said police are focusing on two types of undocumented immigrants.

"One is the over-stayers and who came illegally, smuggled themselves through the borders, or were smuggled in," he said. "But as far as the others who have documents and have shifted from one job to another without informing the authorities, I think their position is being rectified."

The Saudi Census Bureau does not break down the exact demographics of Manfouha.

There are no official numbers yet on how many migrants are affected by the government crackdown. Images from Manfouha show dozens of migrants waiting for buses and taxis as they prepare to leave the neighborhood.

Al Maeena said many Saudis welcome a crackdown on illegal immigrants, but there are questions about who will fill their jobs. "Most of the jobs that are being done are menial jobs," he said. "They are drivers. They drive septic tanks, they do work in farms. They do many jobs that the Saudis don't."