Iraq's prime minister on Thursday described the US handover Thursday to Iraqi authority of the heavily fortified Green Zone and Saddam Hussein's presidential palace as the most visible sign that his country has regained its sovereignty. At a ceremony marking the transition, Nouri al-Maliki said he will propose January 1 be declared a national holiday to commemorate what he called "Sovereignty Day" - the day Iraq took the lead in security away from US forces, regained control of its airspace, and reclaimed a wide swath of downtown Baghdad's Green Zone. The area that became known as the Green Zone on the west bank of the Tigris River was occupied by the United States shortly after the 2003 US invasion and walled off from the rest of the city. The takeover is part of a security deal with the United States. Until Wednesday, the palace formally served as US Embassy and headquarters of the US military in Iraq, although a new American embassy had been built on the other side of the Green Zone, which is also known as the International Zone. Thursday's palace handover was mostly ceremonial, as US diplomats and military officials long since moved to the new embassy building. "This palace is the symbol of Iraqi sovereignty and by restoring it, a real message is directed to all Iraqi people that Iraqi sovereignty has returned to its natural status," al-Maliki said. "We have the right to be proud and to be happy and to hold celebrations these days, especially on this day," said al-Maliki, adding he would submit his proposal to the cabinet. "This day is to be remembered and we have the right to consider it a national day." The 10-square-kilometer area along the Tigris was separated from the city by a 4-meter high wall of reinforced concrete, dotted with watch towers and machine gun nests. Restricted to US and Coalition personnel, several other embassies, Iraqi ministries and parliament, it was considered the most potent and visible sign of American occupation and had often come under insurgent attacks. Although now under Iraqi control, it is unlikely to be dismantled any time soon because of the violence persisting around Baghdad - despite an overall dramatic drop in attacks and killings nationwide. There were two violent incidents Thursday in northern Iraq. In the northern city of Mosul, where the fight against al-Qaida in Iraq continues, a parked truck bomb killed three police officers trying to search it and wounded a bystander. In the city of Kirkuk, also north of Baghdad, Iraqi and US troops killed three suspected al-Qaida gunmen during a raid, police said. Violence around Iraq had plunged in 2008, with attacks declining to an average of 10 a day from 180 a year ago. The murder rate in November was less than 1 per 100,000 people - far lower than many cities in the world. US military deaths in Iraq also plunged by two-thirds in 2008 from the previous year, a reflection of the improving security following the US military's counterinsurgency campaign and al-Qaida's slow retreat from the battlefield. According to a tally by The Associated Press, at least 314 US soldiers died in Iraq in 2008, down from 904 in the previous year. In all, at least 4,221 US soldiers have died in Iraq since the war began in 2003. For Iraqis, the fatalities had also plunged: During 2008, at least 7,496 Iraqis died in war-related violence according to an AP count, including 6,068 civilians and 1,428 security personnel, down 60 percent from 2007. The Associated Press tally does not reflect a comprehensive total for Iraqi deaths because reports do not come in from all of the country. The estimate, however, has proven accurate for tracking trends. The plunge in violence in Iraq follows the US "surge" of 2007, when thousands of additional troops were sent in to try to rein in a country that appeared to be on the verge of disintegration. That was coupled with a counterinsurgency campaign that included a decision by Sunni tribesmen to switch allegiances and fight al-Qaida. A focused effort to rout Shiite extremists gave US and Iraqi forces the upper hand.