At least three police recruits were killed by the car bomb, and another four people also died, although officials couldn't immediately say whether they were recruits or civilians. Thirteen people were wounded, the Diyala police said. The bus had been traveling to a training center in Baqouba, 35 miles northeast of Baghdad.
In the capital, gunmen in two cars opened fire on laborers, killing five, police Capt. Qasim Hussein said.
Meanwhile, in a step toward peace, Iraq's main Sunni Arab group made an unprecedented trip north to see the Kurds and agreed Monday for the first time on broad outlines for a coalition government possibly opening a way out of the political turmoil that has gripped the country after disputed elections.
In other developments:
"We started (Sunday) to supply the tankers with oil products after the government promised to secure them along the highways," Ahmed Ibrahim Hamadi said Monday.
Iraqi Oil Minister Ibrahim Bahr al-Uloum said Monday he resigned after the government last week gave him a forced vacation and replaced him with deputy prime Minister Ahmad Chalabi.
Al-Uloum said he resigned because the government raised fuel prices by up to nine times on Dec. 19, a decision he had strongly criticized.
Prime Minister Ibrahim al-Jaafari and the ministers of defense and education were welcomed by President Jalal Talabani, a Kurd, in Sulaimaniyah, 160 miles northeast of Baghdad, on Monday.
Al-Jaafari is a leading member of the United Iraqi Alliance, a religious coalition of majority Shiites that won the most votes in the Dec. 15 parliamentary elections, according to preliminary results.
Sunni Arabs made their opening bid Sunday in what could be protracted negotiations to form a new government. Leaders of the minority's main political group, the Iraqi Accordance Front, traveled to the northern city of Irbil for a Monday meeting with the president of the Kurdish region, Mazoud Barzani.
In Baghdad, a promise of Iraqi army protection for tanker truck drivers targeted by insurgents reopens Iraq's main refinery — a last ditch effort by the Shiite-led government to avert a fuel crisis that has led to deadly riots and the resignation of the country's oil minister.
Violence following the Dec. 15 parliamentary elections was unabated. A suicide car bomber targeted a busload of police recruits north of Baghdad, killing seven people, and gunmen in the capital killed five workers, police said.
As part of the bargaining for a new coalition government, President Jalal Talabani assured Prime Minister Ibrahim al-Jaafari that his fellow Kurds would not object if the Shiite United Iraqi Alliance that has a strong election lead again nominates him for the post.
But it was the agreement struck by Kurdistan regional President Massoud Barzani and representatives of the main Sunni Arab Iraqi Accordance Front that opened the way for a new broad-based government. It also drew the ire of smaller minority parties and secular groups.
"They will be part of a future government," Foreign Minister Hoshyar Zibari, a Kurd who sat in on the meetings.
Sunni Arabs and secular parties, such as the one headed by Shiite former prime Minister Ayad Allawi, have complained the elections were tainted by widespread fraud and intimidation. They have demanded a rerun in some provinces, including Baghdad.
With their agreement, the Accordance Front seems to have broken a pact to only discuss those complaints during their meetings with the Kurds. Opposition groups are waiting for a team of international monitors — which arrived in Baghdad on Monday — to assess the elections and examine their complaints, which number about 1,500. The United Nations has called the polls credible.
"We were shocked today when we heard that our brothers, who signed agreements with us yesterday to discuss just the fraudulent elections with the Kurdish leaders, instead were discussing forming a national unity government," Saleh al-Mutlaq, the head of the Sunni Arab National Dialogue Front, told The Associated Press.