The violence began when east Africans protesting the crackdown barricaded themselves in the narrow streets of Manfouha, throwing stones, threatening people with knives and damaging cars. Days earlier, an Ethiopian man was killed by police chasing down migrants.Violence broke out again days later in the same neighborhood, and a Sudanese man was killed in clashes Wednesday. In the Red Sea coastal city of Jiddah in the poor al-Azaziya neighborhood, clashes also broke out when police combed the area for migrants. "This is not racism or a lack of respect for diversity, but you cannot imagine how much negative comes from these groups instead of positive. These people, every day, cause problems," said Jiddah resident Abdulaziz al-Qahtani, who posted online video from the Riyadh clashes that he said a friend took. Since the weekend clashes, Saudi officials say 23,000 Ethiopians, including women and children, have turned themselves in to the police. Authorities say most had no documentation of ever entering the kingdom and are being held in temporary housing ahead of deportation. Ethiopia's Foreign Ministry said in a statement that officials in Addis Ababa sought an explanation from Saudi Arabia's envoy over the "mistreatment" of Ethiopians in the kingdom. Workers from neighboring Yemen also face harassment. Yemeni Nobel Peace Prize Laureate Tawakkol Karman posted a picture last week on her Facebook page of what appeared to be a Saudi man in his car grabbing hold of a Yemeni man for a police officer. Saudi columnist Abdul-Rahman al-Rashed cautioned Saudis to remember that without "a strong state and oil revenues" they too may have emigrated in search of work. "Those deprived of the chance of a proper life can understand the feeling of those wanting to seek a better life," he wrote in the Asharq al-Awsat newspaper. ___ Batrawy reported from Dubai, United Arab Emirates.