Updated

U.S. forces on Saturday captured seven suspected insurgents believed to be behind an attack on the U.S. Embassy in Baghdad that killed two Americans and wounded six.

The rocket attack killed one civilian Defense Department employee and one naval officer. Of the six injured Americans, four were military and two were civilians, a military official said. A State Department spokesman said none of their injuries were life-threatening.

Earlier on Saturday, eight people were killed in a homicide bombing and a roadside explosive killed a U.S. soldier.

The explosion rocked the U.S. Embassy a little past 7 p.m. on Saturday when a rocket landed outside the southern edge of the palace that houses American civilians and military personnel. The embassy is approximately 350 yards from the nearest border of the heavily fortified Green Zone (search). Concrete barriers and a 10-foot-high fence surround the compound, meaning the attack was probably the result of indirect fire.

U.S. forces were able to trace the trajectory of the rocket — which was fired from a distance of 15.1 kilometers — and eventually homed in on two cars driving away from the launch site, officials told FOX News.

The cars drove to two separate houses, where U.S. forces apprehended seven people. Five of the suspects tested positive for rocket material, but all seven were taken into custody for questioning in a Baghdad detention facility.

None of the captives are "big catches," officials said. The suspects' countries of origin are unknown, but they are believed to be Iraqi. Officials also believe the group had plans to carry out another attack.

Embassy employees had been urged to stay off the streets as the election neared, sources told FOX News. The embassy — which houses about 3,500 State Department employees, USAID workers and other American officials — has been a popular target among insurgents.

Earlier on Saturday, eight people were killed when an explosives-laden man blew himself up in front of a police station in Khanaqin, a Kurdish town 70 miles northeast of Baghdad on the Iranian border. Police Col. Mohammed al-Khanaqini said the man detonated himself between a U.S. base and a courthouse.

Also on Saturday, a U.S. soldier from Task Force Baghdad was killed by a roadside bomb in a western district of the capital, the military said.

More than 40 U.S. troops have died in the past three days. Iraq's interim prime minister said that the "success" of the election would mean America's sacrifices were made in the service of freedom.

"They have not fallen in vain. They have fallen for a just cause ... and we are witnessing now some of the results of this very sacred cause," Ayad Allawi (search) told FOX News. "Their blood and the blood of Iraqi soldiers have not gone in vain."

The streets of Baghdad were largely empty, due to dusk-to-dawn curfews, barricades, restricted intra-province travel and sealed borders ahead of Sunday's historic election. But bursts of heavy gunfire exchanges between U.S. and Iraqi forces and insurgents, several large explosions and American fighter jets continued to rattle the capital city.

Baghdad's international airport was also closed, and private vehicles restricted.

Polls opened at 7 a.m. local time, 11 p.m. EST, and Iraqis started filtering into polling stations shortly thereafter.

The Associated Press contributed to this report.