( CNN ) -- Gunmen who stormed an Iraqi university on Saturday used students as human shields and clashed with security forces , authorities said . Forces have surrounded al-Anbar University in the city of Ramadi and are attempting to retake the campus from the attackers . The campus is about 110 kilometers ( 68 miles ) west of Baghdad . The gunmen are believed to be members of the Islamic State in Iraq and Syria , a rogue Sunni Muslim extremist group formerly affiliated with al Qaeda , also known by its acronym ISIS , police said . Approximately 1,200 students , professors and staff who live in the campus residential buildings were present during the attack ; nearly 20 students were slightly injured , officials said . The majority of students were able to flee , but some are still inside , police officials told CNN . The Al-Anbar University attack comes amid a wave of violence that has taken Iraq by storm . Also Saturday , six roadside bombs exploded in the capital of Baghdad , killing at least 33 people and injuring 72 others , police officials said . The explosions occurred in a busy commercial Shiite neighborhood , targeting mostly civilians , police said . This year , Iraq has witnessed some of the worst violence since 2008 . The United Nations reported that May was the deadliest month since the beginning of the year . The escalating violence in recent months has left hundreds dead , raising fears it could return Iraq to the level of violence in 2006 and 2007 , when bodies littered the streets .
Six roadside bombs kill dozens in Baghdad . The attacks come as Iraqi forces are battling to retake the city from ISIS militants who have seized large parts of northern and western Iraq. Students used as human shields , police say .