Iraq anxiously awaited the arrival of its Asian Cup soccer champs Friday, but most Baghdad residents would be barred from the homecoming celebration because of security.

The U.S. military, meanwhile, announced the deaths of four more American soldiers.

The national team, which hasn't played a home game in 17 years, landed at Baghdad's international airport Friday evening and traveled by bus in a convoy to the heavily fortified Green Zone in central Baghdad. Iraqi officials, led by Deputy Prime Minister Barham Saleh, met the team upon its arrival, according to government representative Bassam al-Husseini.

• Iraqi Soccer Team Wins Asian Cup 1-0

• Visit FOXNews.com's Iraq Center for more in-depth coverage.

But at least three of the team's stars -- including captain Younis Mahmoud, Nashat Akram and Hawar Mulla Mohammed -- were not believed to be with them. Mahmoud, a Sunni Arab who scored the winning goal in Iraq's 1-0 Asian Cup final win over Saudi Arabia, has said he feared for his life if he returned to Iraq to celebrate the stunning victory.

Prime Minister Nouri al-Maliki planned a welcoming celebration in the Green Zone, home to the U.S. Embassy and the Iraqi government headquarters, al-Husseini said.

"I wish the celebration would take place in al-Shaab stadium, but that is impossible for security reasons," said Mohammed Kadhom, 35, who works at the country's oil ministry. Al-Shaab is a huge, Saddam Hussein-era facility on the capital's east side.

"It is sad that we can't receive our national team in a public celebration as others do, I myself fear for their safety," Kadhom said.

Vehicles were banned from Baghdad's streets for four hours coinciding with prayer services on Friday, for a regular weekly curfew on the Muslim holy day. Several rings of security around the Green Zone would prevent ordinary Iraqis from welcoming the team, which has already had celebrations in Dubai and Amman en route back from Indonesia, where the winning match was played.

"It is an incomplete joy, because all other people welcome their winning teams in the streets of their capitals and we in Iraq had to be the last ones to receive them, after the (United Arab) Emirates and Jordan," said Baghdad resident Naeem Abdullah, 40.

Meanwhile, the U.S. military announced the combat deaths of four more soldiers in Baghdad, including three killed Thursday in a single roadside bombing on the city's east side. The blast wounded 11 other U.S. troops. Another soldier was killed and three wounded in combat the same day in western Baghdad, the military said.

At least 3,663 members of the U.S. military have died since the Iraq war started in March 2003, according to an Associated Press count. The figure includes seven military civilians.

Also Friday, an aide to Iraq's top cleric was killed in the Shiite holy city of Najaf, a security official there said on condition of anonymity out of safety concerns.

Fadhil al-Akil was in charge of collecting a Shiite religious tax known as "khoms," which is paid to Grand Ayatollah Ali al-Sistani and used to run his seminaries and charities.

Gunmen approached al-Akil and shot him dead around 10:30 p.m. Thursday, the security official said.

He was the second al-Sistani aide murdered in less than two weeks, raising questions about the Shiite cleric's own safety. Sheik Abdullah Falak al-Basrawi, who also collected religious taxes for al-Sistani, was stabbed to death inside the cleric's fortified compound on July 27 or 28th, police said, and a security guard was arrested afterward.

A month earlier, yet another aide was killed in a drive-by shooting.

It is unclear whether the killings are part of internal Shiite disputes or the work of Sunni insurgents opposed to the vast influence enjoyed by al-Sistani over Iraqi Shiites and politics.

Al-Sistani, who rarely leaves his compound and doesn't grant media interviews, has been the target of at least one assassination attempt since 2003. The cleric, who is in his 70s, commands the deep respect of Iraq's majority Shiites. A death other than one of natural causes could spark riots by millions of his followers and fuel more sectarian violence.

Najaf has been relatively safe compared to the violence in Baghdad or other cities in the volatile center and north of Iraq, but a series of unsolved murders in recent months have struck clerics, academics and security officials. None of the killings had an obvious motive or could be linked to tribal, personal or religious disputes.

In other violence, police said a mortar and rocket-propelled grenade landed on homes late Thursday in Khan Bani Saad, a mixed town northeast of Baghdad, killing four civilians — two of them children. Six others were wounded in the shelling, police said.