Four people were killed and nine, including two policemen and a woman, wounded during violence in the eastern province of Saudi Arabia, according to the official Saudi Press Agency. Police exchanged fire with gunmen who \"infiltrated\" the funeral of another protester, the interior ministry said Thursday. The new deaths late Wednesday brought to four the toll of protests that began in Qatif on Monday, SPA said. \'Unknown criminals\' \"These casualties were sustained during exchange of fire with unknown criminals who infiltrated citizens and opened fire from residential areas,\" it said. The ministry claimed that \"a number of security checkpoints and vehicles have since Monday been increasingly coming under gunfire attacks in the Qatif region by assailants motivated by foreign orders.\" \"Security forces have been exercising self restraint as much as possible,\" it said. \"Several incidents of fire exchange took place during the funeral of one of those ... which caused the death of two citizens and wounded three others,\" it added.