Suicide bombers assaulted an Iraqi television station headquarters Monday, killing five journalists in the latest in a series of attacks against the media, police officers said. The dead in Tikrit, north of Baghdad, were Salaheddin television's chief news editor, a copy editor, a producer, a presenter and the archives manager, the officers said. Two of the bombers blew themselves up during the attack, and security forces killed the other two when they stormed the building in the assault, in which five Salaheddin employees were wounded. Last week, militants attacked the Tikrit city council headquarters, and a council member and two police were killed. Iraq has come in for repeated criticism over the lack of media freedom and the number of unsolved killings of journalists. The country is currently experiencing the worst violence against journalists in years, with 12 killed in attacks since October 5. Other violence on Monday killed 17 people, as officials said unrest in Iraq was being fuelled by the Syrian civil war. Mortar rounds struck an army base in the Abu Ghraib area west of Baghdad, killing a brigade commander, three other officers and two soldiers, security officials said. Two days earlier, five senior officers, including a divisional commander, and 10 soldiers were killed during an operation against militants in the mainly Sunni western province of Anbar. And bombings and shootings in Baghdad killed at least nine people and wounded 21 on Monday, while two more people died and eight were wounded in Tikrit and Baquba. Violence has reached a level not seen since 2008, when Iraq was just emerging from a brutal period of sectarian killings. On Sunday, the United States called for regional leaders to work to cut funding and recruitment for two jihadist groups -- the Islamic State of Iraq and the Levant and Al-Nusra Front -- saying foreign fighters were going to Syria and then carrying out attacks in Iraq. ISIL operates in both Syria and Iraq, while the Al-Nusra Front is based in Syria but has also been linked to Iraq. Washington called for "active measures to police the funding and recruitment for these groups... and deter the flow of foreign fighters into Syria, many of whom later conduct suicide bombings against innocent civilians in Iraq," State Department spokeswoman Jen Psaki said. Iraqi defence ministry spokesman Mohammed al-Askari also said the situation in Syria was driving violence in Iraq. He told AFP aerial photographs and other information pointed to "the arrival of weapons and advanced equipment from Syria to the desert of western Anbar and the border of Nineveh province," referring to two Sunni-majority areas that border Syria. This has encouraged Al-Qaeda-linked militants to "revive some of their camps that were eliminated by security forces in 2008 and 2009," Askari said, adding that aerial photos showed 11 militant camps near the border with Syria. "Photographs and intelligence information indicate that whenever there is pressure on armed groups in Syria, they withdraw to Iraq... to regroup and then carry out terrorist operations in the two countries," Askari said. On Sunday, Prime Minister Nuri al-Maliki said a Sunni Arab anti-government protest camp in Anbar has become a "headquarters for the leadership of Al-Qaeda," calling on legitimate protesters to leave before security forces move in. Protests broke out late last year in Sunni-majority areas of Iraq, where people complain of being both marginalised by the Shiite-led government and unjustly targeted by heavy-handed security measures. Experts say widespread Sunni anger has been a major factor in the heightened unrest this year. The number of deaths surged after security forces raided an anti-government protest site near the northern town of Hawijah on April 23, sparking clashes in which dozens died. More than 6,650 people have been killed in Iraq since the beginning of the year, according to AFP figures based on security and medical sources.