Attackers struck first at the entrance of the Australian embassy around 7 a.m. local time, detonating a truck bomb that killed two people and wounded several others, including Australian soldiers.
A group led by Jordanian militant and al-Qaida ally Abu Musab al-Zarqawi claimed responsibility for the embassy attack.
A short time later a car bomb was detonated at a police station in eastern Baghdad, killing six people, according to the Iraqi Interior Ministry.
Later in the day three more bomb-laden vehicles exploded in separate attacks at an Iraqi military post, a security checkpoint near Baghdad International Airport and a Shiite Muslim Mosque. Six Iraqis were reportedly killed in the three attacks.
An official with the Patriotic Union of Kurdistan was also killed Wednesday in Baghdad when insurgents fired on his vehicle.
Car bombings, shootings and assassinations were also reported in other Iraqi cities Wednesday.
An Iraqi policeman was killed by a car bomb in the city of Hillah south of Baghdad. Two human rights workers were found dead in Kirkuk with bullet wounds to the head and chest. American soldiers and insurgents battled in Mosul after a car bomb was detonated near a U.S. convoy.
Carlos Valenzuela, the chief U.N. election adviser in Iraq, said the wave of violence, which he described as "high and very serious," is designed to disrupt elections scheduled for the end of the month. But Valenzuela said only sustained attacks over time or mass resignations of election workers would be able to stop the elections.
U.S. troops have stepped up raids designed to head off insurgent attacks.
Sunni Muslim groups have called for boycotting the elections for fear the results will lead to oppression by the Shiite Muslim majority. Some Sunni extremists have reportedly resorted to violence in attempt to stop the elections.
In addition, U.S. officials have said that Muslim extremists, who want to expel all westerners from the country, and Saddam Hussein loyalists have banded together to attack military and civilian targets in hopes of thwarting the elections. On Monday, 22 people were killed in attacks across Iraq.
A White House spokesman said President Bush had talked to Iraqi officials by phone Wednesday about plans for the elections. Press secretary Scott McClellan said the United States is working with Iraqi security forces "to provide as secure an environment as possible so that as many Iraqis as possible can participate in the elections."
"It's important that we continue doing everything we can to support the interim government and support the Iraqi people as they move forward with elections," McClellan said. "Elections will be an important step toward derailing their ambitions of returning to the past."
McClellan also acknowledged that a post-election Iraqi government might ask for the withdrawal of U.S. troops.
"Iraq is a sovereign nation. Those are always issues that we discuss in close consultation with the host government, as we do in any country," McClellan said.