The reinforcements included Iraqi aircraft and tanks.
"The largest portion of those forces have arrived already. They are Iraqi army forces and include troops, mechanized troops and air force," said Defense Ministry spokesman Mohammed Askari. "The plan will be similar to the ones implemented in Baghdad and Diyala [province]."
The U.S. military said Sunday that it had no information about any Iraqi military operations in Mosul.
In the last year, U.S. and Iraqi forces have mounted major campaigns to take back areas under the control of Sunni Arab militants, benefiting from the additional 28,500 American troops that arrived in the country during the first half of 2007. Al Qaeda-linked militants have lost the upper hand in Baghdad, where many former insurgents have made alliances with U.S. forces. In Diyala, insurgents remain active.
At least 38 people were killed in Mosul on Wednesday, when militants blew up a building. The next day a suicide bomber assassinated the province's police chief.
The violence prompted Prime Minister Nouri Maliki to pledge to take back Mosul, which is seen as a stronghold for Al Qaeda in Iraq after militants fled north under pressure from U.S.-led forces in Baghdad and in Anbar province.
Mosul, Iraq's third-largest city with 1.7 million people, was already rife with tensions between Arabs and Kurds.
In other developments, a fire was burning today at Iraq's central bank in Baghdad, but no one was hurt, police said. The bank manages Iraq's monetary policy. It was not clear whether any documents or currency were damaged.
The U.S. military announced that two American soldiers died in bomb attacks around Baghdad over the weekend. At least 3,934 U.S. troops have died in the Iraq war since the American-led invasion of March 2003, according to the independent website icasualties.org.
In the capital, the former director-general of east Baghdad's water and sewage systems, his wife and his daughter were beheaded in their home Sunday, police said. The man's nephew also was stabbed and died later at the hospital.
The former official, Ahmed Jawad Hashim, had served under Saddam Hussein, police said. He had returned to work six months after the 2003 invasion and retired four months ago, police said.
Meanwhile, the Iraqi Accordance Front, a Sunni bloc that quit the Cabinet in August, began talks with the government Sunday about returning members to their posts, said lawmaker Khalaf Ayan.
Times staff writers Saif Hameed and Caesar Ahmed contributed to this report