BAGHDAD -- Suicide bombers struck a Shiite pilgrimage in Baghdad and a Kurdish protest rally in northern Iraq on Monday, killing at least 57 people and wounding nearly 300, police said.

Three female suicide bombers blew their explosive vests in the middle of pilgrims in Baghdad, moments after a roadside bomb attack, killing at least 32 people and wounding 102, Iraqi officials said.

In the oil-rich northern city of Kirkuk, 25 people were killed and 185 wounded when a blast tore through a crowd of Kurds protesting a draft provincial elections law, officials said.

Local police said remains recovered from the scene showed the attacker was a woman. The U.S. military confirmed a suicide bombing but said there was no indication the attacker was a woman.

The bombings were a devastating blow to the Iraqi public's growing confidence of recent security gains that have seen violence in Iraq drop to its lowest levels in more than four years.

A senior U.S. military official blamed al-Qaida in Iraq for the attacks in Baghdad. The attacks come ahead of U.S. and Iraqi military operations in early August aimed at routing out insurgents from rural hideouts in northern Iraq and solidify recent security gains in urban areas.