A Muslim civil rights group said Tuesday it's concerned that the U.S. government is delaying the shipment of passports to those who are trying to make religious pilgrimages to Saudi Arabia.

The Council on American-Islamic Relations raised the issue after a northern Virginia mosque reported that 17 people missed their flight to Saudi Arabia when their passports were temporarily seized. The U.S. Customs and Border Patrol bought replacement tickets for those passengers, the mosque said.

On Tuesday, the council said it had learned of three other packages sent via UPS from California containing pilgrims' passports with hajj visas — for travel to Mecca — being held up by security checks or government seizure.

"The American Muslim community needs to know whether packages sent from point to point within our borders are being screened based on the religion of the sender or recipient, and whether or not such packages can be seized and opened by government officials without a warrant," said CAIR National Communications Director Ibrahim Hooper.

Hajj, a pilgrimage to Islam's holiest city, Mecca, is a requirement for all able-bodied Muslims who can afford it. The pilgrimage is a once-in-a-lifetime opportunity and many people save for months or years to pay for the trip, said Khadija Athman, the council's national civil rights manager.

Saudi Arabia issues special visas through approved travel agencies to people traveling to the country for hajj.

Athman said two California travel agents arranged hajj visas with the consulate there and sent out packages with passports for travelers in Minnesota, Seattle, California and northern Virginia.

The package for the northern Virginia travelers was sent via UPS on Nov. 1 and was expected the following day, said Rafi Uddin Ahmed, vice president of the Dar AlNoor mosque in Manassas, Va. The flight was last Friday.

"UPS kept saying they lost the package," Ahmed said. "But finally Friday morning they posted that the package was seized by a government agency."

Ahmed said several agencies were contacted before the mosque learned that Customs and Border Patrol was responsible, and while staff were professional and polite, the package did not arrive until Saturday.

He confirmed that the U.S. Customs and Border Patrol bought replacement tickets for the 17 travelers after they missed their flight.

"CBP did the right thing by making the pilgrims whole again," Ahmed said.

An agency spokesman declined to comment on the case.

The customer was told that the package had a "government seizure exception," said UPS spokeswoman Lynette McIntyre. But she would not say which agency was involved in the case or comment on whether UPS calls on Customs and Border Patrol to check packages.

A Minneapolis travel agency reported a similar experience to the civil rights group. After clients' passports were shipped by overnight mail last week, tracking information on UPS' website said they were flagged for a security check, then they were delivered Tuesday without an explanation, said Abdirahman Hashi, manager of Al Salama Travel in Minneapolis. The passports arrived just in time for his clients' coming Wednesday flight.

"What we're asking is why? If they had any issue, they should have notified us," Hashi said.

McIntyre said UPS' tracking system shows that that package was mailed Monday in California and was delivered Tuesday, so there was no delay.

The four reports don't seem like isolated incidents to Athman.

"It's too much of a coincidence," Athman said. "Four packages coming from California to different recipients with the same contents: passports, visas for hajj? It's too much of a coincidence to happen within the same week."

The reports follow an al-Qaida mail bomb plot that was foiled last month when two explosive packages shipped from Yemen via UPS and FedEx were intercepted.

"We all realize living in current times the necessity of safeguarding Americans and keeping the country safe. However, once they had found that there was no imminent danger they should have cleared the package right away," said Ahmed of the northern Virginia mosque. "I do have to wonder, if that package did not bear a Muslim name, would it have happened?"