10-01) 04:00 PDT Baghdad -- The streets of Baghdad were mostly quiet Saturday, with the capital under total lockdown a day after U.S. troops arrested a bodyguard of a Sunni Arab political leader on suspicion of planning suicide bombings inside the fortified Green Zone.

The daylong curfew was the first to ban both pedestrian and vehicle traffic since the U.S.-led invasion in 2003, underscoring the security concerns enveloping Baghdad. It was requested by U.S. military officials concerned about the surge in suicide bombings and other violence since the Muslim fasting month of Ramadan began last weekend.

"There is no single reason," said Lt. Col. Barry Johnson, a military spokesman. "What we found was that implementing curfews from time to time helps break up the cycle of violence. It seemed like a prudent measure at this time to recommend a curfew."

The measure was announced a few hours after U.S. troops raided the residence of Adnan al-Dulaimi, leader of the largest Sunni Arab coalition in Iraq's parliament, and took into custody a bodyguard, identified by al-Dulaimi's supporters as Khudir Farhan.

"Credible intelligence indicates the individual, a member of Dr. Dulaimi's personal security detachment, and seven members of the detained individual's cell were in the final stages of launching a series of (car bomb) attacks inside the International Zone, possibly involving suicide vests," the U.S. military said in a statement.

The suspect, the statement added, was linked to a car-bomb-producing network based in south Baghdad and was believed to be a member of the group al Qaeda in Iraq. U.S. soldiers searched a security trailer and the suspect's car but did not enter al-Dulaimi's home, said the statement.

On Saturday, al-Dulaimi denied that the bodyguard had any connections to terrorists.

"In the name of God, this news is absolutely not true. This is a suspicion only," he said on Al-Arabiya television. "This guard has joined the security force one month ago, and we have not noticed anything suspicious. The investigation will prove his innocence."

A few hours later, the U.S. military altered its statement to say that "this operation in no way implies (al-Dulaimi) was associated with any illegal activity; he was not the target in this operation."

In Baghdad's Karrada neighborhood on Saturday, the main road was empty save for police cars. Some food stalls remained open, and some young residents flouted the curfew and walked on the streets. Many expressed frustration, saying the curfew would achieve nothing to ease their lives.

"My life is destroyed because of the politicians and the government," said Firas Hatem, 31. "What have we gained from the curfew? Did they destroy the militias? Have they provided us with gas or electricity or food? The curfew has pushed prices up, and everything is expensive -- and the cheapest thing is us, meaning the human being."

In Tal Afar, in the north, a suicide bomber detonated his explosives-rigged car, killing two civilians and injuring 30. In the southern city of Basra, provincial Gov. Mohammed al-Waeli escaped an attempt on his life Saturday morning, when gunmen attacked his convoy, wounding three of his bodyguards.

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