Iraqi officials say a wave of coordinated bombings and shootings has killed at least 110 people in the deadliest day of violence in that country in more than two years.

Officials say the violence that struck 15 cities Monday also wounded more than 200 people. The last time the casualty toll reached that high was on May 10, 2010.

The worst attack Monday was in Taji, 20 kilometers north of Baghdad, where nearly 40 people were killed. A series of explosions at a housing complex was followed by a later blast that targeted police who arrived at the scene.

There was no immediate claim of responsibility.

The United States condemned the attacks, but it said that despite the setback, Iraq is not nearly as violent a place as it was in the past. A White House spokesman said Iraqi security forces have been trained and have the capacity to deal with their own security.

The violence comes after jihadist websites posted a message Saturday, purportedly from the leader of al-Qaida's affiliate in Iraq, saying the group is starting a “new phase.” The audio message from a speaker identified as Abu Bakr al-Baghdadi says the Islamic State of Iraq is planning to attack court officials, and to free prisoners.

In June, the group claimed responsibility for a wave of car bombings that killed 72 people and wounded nearly 260 others.

The attacks Monday included one in which gunmen killed at least 15 Iraqi soldiers at a military base in northeastern Iraq, a series of explosions in the northern city of Kirkuk, and a car bombing in Baghdad.