Baghdad (CNN) -- Suspected al Qaeda militants clashed with Iraqi forces Thursday, in attacks that began two days after a wave of violence across Iraq.
At least five federal police officers were killed and four others were wounded during the clashes in Hadida, about 50 miles north of Baghdad, Interior Ministry officials said. The fighting erupted late Wednesday and carried on through early Thursday.
Police called for backup from the army and sealed off the Hadida area. An army helicopter was forced to make an emergency landing after insurgents fired on it, but no one was killed, the officials said.
Hadida is in Diyala province, near the city of Baquba, once an insurgent stronghold.
Monday's violence, in which 103 people were killed, evoked the bloodiest days of the war, when random and targeted attacks routinely killed scores of people daily. Attacks have declined sharply since their peak in 2006, but insurgents have continued to target civilians and security forces since the United States withdrew its forces in December.
Before Monday's attacks, the deadliest day this year had been June 13, when coordinated attacks nationwide killed 93 people.
The Islamic State of Iraq, an al Qaeda-linked group, claimed responsibility for Monday's attacks. In a statement posted on radical jihadist websites, the group praised the operation, calling it a "new phase."
This week's attacks coincide with an emerging political crisis in Iraq, which faces an increasingly fractious legislature as Shiite, Sunni and Kurdish political blocs increasingly seem at odds.
Shiite Prime Minister Nuri al-Maliki has struggled to forge a power-sharing agreement and has yet to fill key Cabinet positions, including the ministers of defense, interior and national security, while his backers have shown signs of wobbling support.