BAGHDAD – U.S. and Iraqi forces on Tuesday raided a sweets factory being used as a headquarters by suspected Sunni insurgents in northern Iraq, which has seen a recent rise in violence as militants have fled a nearly 4-month-old security crackdown in Baghdad.

The discovery illustrated the challenges faced by American and Iraqi troops trying to stop the unrelenting violence even as militants consistently find new ways to thwart stepped-up security measures.

The Bush administration, meanwhile, stepped up pressure on the political front, sending the No. 2 State Department official to Baghdad, where he met with Iraqi Prime Minister Nouri al-Maliki and other Iraqi officials.

Al-Maliki assured Deputy Secretary of State John Negroponte that his government would persist in its efforts to pass a controversial oil law as well as a bill allowing former members of Saddam Hussein’s Baath party to return to government jobs and join the military.

The meeting came at a time when the Americans are pressing the Shiite-led government to show progress on political reforms to bring the disaffected Sunni minority into the political process and stem support for the insurgency.

“A lot of missions are ahead of us, on top of them is developing our security forces to handle their national roles in fighting the al-Qaida terrorist group, Saddamists and militias to impose law and order in all the country,” al-Maliki told Negroponte as the two men sat on gilded chairs in the prime minister’s office in Baghdad’s fortified Green Zone.

U.S. and Iraqi officials have pinned their hopes on the adoption of the laws as well as the Baghdad operation to quell sectarian attacks, but Iraq’s fractured political parties have failed to reach final agreement on any of them.

The New York Times reported Tuesday that Adm. William Fallon, the top U.S. commander in the Middle East, warned al-Maliki on Sunday that the Iraqi government needs to make tangible political progress by next month to counter growing congressional opposition to the war.

He singled out the oil bill, which if approved is expected to encourage foreign oil companies to invest in Iraq and spur the country to attain its goal of doubling current production of 2.5 million barrels a day by 2010.

Al-Maliki’s Cabinet signed off on the bill in February and sent it to parliament, a move that the Bush administration hailed as a major breakthrough. But parliament has yet to consider the legislation, which faces opposition from Sunnis who fear being left out of the wealth and Kurds who want greater control of oil fields in the north.

A man who helped draft the oil legislation offered a pessimistic assessment Tuesday at a news conference at the Center for Strategic and International Studies, a Washington think tank.

Tariq Shafiq, who runs a petroleum consulting firm in London, said “there is no sign of a compromise” that would lead to final approval by the parliament.

Shafiq blamed the holdup on a lack of security in Iraq, where he said “people do not know if they are going to live the next day,” as well as on corruption.

The legislative body faced a new distraction after lawmakers voted Monday to replace the parliament speaker, whose behavior was viewed by many as unbecoming and occasionally erratic.

Mahmoud al-Mashhadani, a Sunni Arab, told a news conference Tuesday he had no intention of resigning. “The speaker of the Council of Representatives is not a toy in the hands of juvenile politicians,” he said. “I refuse to resign and will take my case to the federal court if I must.”

Lawmakers gave the Iraqi Accordance Front, the largest Sunni Arab bloc in parliament, a week to name a replacement. Al-Mashhadani, a former physician once jailed by Saddam Hussein, will keep his seat but lose his position as speaker.

Violence persisted on Tuesday, with at least 45 people killed or found dead, including nine soldiers and civilians killed in clashes and drive-by shootings. Police said 15 al-Qaida militants also were killed in fighting with joint U.S.-Iraqi forces, although the military did not immediately confirm that.

Suspected Sunni insurgents also bombed and badly damaged a span over the main north-south highway leading from Baghdad on Tuesday — the third bridge attack in as many days in an apparent campaign against key transportation arteries.

The U.S. and Iraqi military offered different accounts of the raid on the sweets factory in Mosul, 225 miles northwest of Baghdad.

The American military said a joint U.S.-Iraqi force had found an ice cream factory in which “individuals associated with the Islamic State of Iraq were operating from,” referring to a Sunni insurgent group, but said it had no reports of mass explosives or chemical fertilizer being discovered and destroyed.

“We also detained an unspecified number of anti-Iraqi forces,” the military said in an e-mailed statement.

Iraqi army commander Brig. Gen. Nour al-Din Hussein, however, said earlier that it was an lollipop factory and the forces found boxes of explosives and two tons of fertilizer in the basement of the facility.

Hussein said the entry room to the al-Arij factory was booby-trapped and the building was empty because the workers fled after apparently being tipped off to the raid. He added an anti-aircraft gun was hidden on the roof.

Hussein, commander of Iraq’s 4th Brigade, said the Christian owner of the lollipop factory was killed three years ago. He said the facility was currently rented to people whom police refused to identify for security reasons.

The troops, who found candy boxes filled with explosives, oxygen cylinders and two tons of fertilizer in the basement, spent three hours destroying the payload in controlled blasts in an industrial area of Mosul, Hussein said. Bodies are often found in the area, located in the city’s eastern section.