Iraqi security forces locked down parts of Baghdad Tuesday and were searching neighborhoods, the capital's chief military spokesman said, in what appeared to be a wide-ranging operation across the city.

While there are hundreds of checkpoints throughout Baghdad, such large-scale lockdowns and searches of neighborhoods have become rare since the height of the insurgency in 2006 and 2007.

The security operation comes as Iraq is preparing for crucial nationwide parliamentary elections in March, and officials have warned that insurgents seeking to disrupt the vote could try to launch attacks as the election nears.

"We imposed strict security procedures and blocked parts of Baghdad neighborhoods to launch search operations," Maj. Gen. Qassim al-Moussawi told The Associated Press by phone.

He gave no details and would not comment on why the measures were imposed or whether authorities were responding to a specific threat.

People in various neighborhoods across the city said no cars were allowed on the normally traffic-clogged streets in their areas, and some schools were closed as part of the security lockdown. In other areas of the city, life continued as normal.

Samir Hassan, a university student in Baghdad, said he returned home after being told that there were no classes.

"I just arrived at the university and then they told us there are no classes, and roads are blocked. The security situation is unstable. They told us, 'You should return,' so we are going home on foot," Hassan said.

The capital has been rocked by a number of high-profile bombings in recent months, mostly targeting government institutions in central Baghdad.

According to an Interior Ministry officer, some security raids on houses have taken place on Haifa Street and in the Fadhil neighborhood in central Baghdad, both former insurgency strongholds. Another security official said authorities were searching the Karkh neighborhood in western Baghdad for weapons and car bombs.

Both officials spoke on condition of anonymity because he was not authorized to speak to the media.