BAGHDAD -- A suicide bomber drove his truck into a police station north of Baghdad on Monday, crumbling the squat concrete building and damaging a nearby school in the deadliest in a series of blasts that killed at least 24 people across Iraq.
Nobody claimed responsibility for the attacks in the capital and two northern areas. But they bore the hallmarks of al-Qaida in Iraq, which has promised an offensive to coincide with the Islamic holy month of Ramadan.
The blast in Dijlah, a village in the Sunni heartland 60 miles north of the capital, tore through a nearby empty school and several stores. At least 13 people -- three officers and 10 civilians -- were killed, and 22 were wounded, police said.
The station, built in the 1980s on a thoroughfare that links Samarra with Tikrit, was poorly protected. It was surrounded by concrete barriers less than one yard high, even though it had been ambushed less than a month ago by dozens of gunmen.
A suicide car bomber also struck a police checkpoint in Tikrit, Saddam Hussein's hometown 80 miles north of Baghdad, killing three officers and one civilian, and wounding 10 other people.
In the capital, a parked car bomb exploded at a market near Baghdad University's technology department, killing five civilians and wounding 15.
A car bombing near the Polish Embassy killed two Iraqis and wounded five, police said. The attack was launched five days after Polish Ambassador Gen. Edward Pietrzyk was wounded in an ambush.
The Polish Charge d'Affaires Waldemar Figaj told The Associated Press that he heard a series of explosions around the embassy Monday morning but the closest appeared to be about 200 yards away and the embassy had no reason to believe it "was targeted in any way."
All police spoke on condition of anonymity because they feared retribution.
The U.S. military announced that two more servicemen were killed in fighting -- a Marine west of Baghdad on Monday, and a soldier near the northern city of Beiji on Friday. At least 3,817 members of the U.S. military have died since the Iraq war started in March 2003, according to an Associated Press count.
Iran, meanwhile, reopened five border crossing points with Kurdish-run northern Iraq on Monday.
The border points had been closed Sept. 24 to protest the U.S. detention of an Iranian official.
The U.S. military has said the official was a member of Iran's paramilitary Quds Force, which is accused of providing arms and training to Shiite extremists. But Iraqi and Iranian authorities have claimed that the detained Iranian, Mahmoud Farhadi, was in Iraq on official business and demanded his release.
The border points were reopened after a Kurdish delegation traveled to Iran to complain the region should not be punished for something the Americans did.
A spokesman for the Kurdish regional government in northern Iraq, Jamal Abdullah, said he hoped the resumed flow of traffic and goods would help rising prices plaguing the region since the closures.
The reopening is in the "economic interests of both countries," Abdullah said, adding that Tehran and Baghdad share the responsibility to "prevent gunmen from having access to either side of the border."
Meanwhile, Iraqi authorities claimed that a former prime minister and a hardline Sunni sheik -- both opponents of Prime Minister Nouri al-Maliki -- were implicated in clashes earlier this year between U.S. and Iraqi troops and a heavily armed cult of messianic Shiites near the holy city of Najaf.
One of the men detained in the fighting said in a videotaped confessions that former Prime Minister Ayad Allawi, a secular Shiite, and Harith al-Dhari, the head of Sunni Association of Muslim Scholars, had contributed financially to the Soldiers of Heaven group.
A lawmaker from Allawi's parliamentary bloc, Izzat al-Shabandar, called the accusations "baseless" and said they were politically motivated. Al-Dhari's representatives said the allegations were still being studied and they had no immediate comment.