Gunmen dressed in police uniforms staged a mass kidnapping at a Baghdad research center Tuesday, prompting Iraq's education minister to order all universities closed until security could be improved.

Government spokesperson Dr. Ali Al-Dabag told FOX News that 20 of the 50 people who were handcuffed and forced into vehicles in a lightning raid at 9:30 a.m. local time have since been released unharmed.

Al-Dabag said the government was responding to the crisis, adding that authorities had already collected information on the identities of the abductors and the whereabouts of the remaining captives.

Earlier reports said from 100 to 150 people, both Shiites and Sunnis, had been kidnapped from the Ministry of Higher Education and Scientific Research, Scholarships and Cultural Relations Directorate in Baghdad's Karradah district.

"I have only one choice which is to suspend classes at universities," Abed Theyab, Iraq's higher education minister, told parliament. "We have no other choice."

Theyab said he was "not ready to see more professors get killed," adding that he had repeatedly petitioned for more university security from the ministries of Defense and Interior, who command the police, but had received none.

"It was quick operation. It took about 10 to 15 minutes," Theyab said. "It was a four-story building and the gunmen went to the four stories." He said the gunmen had at least 20 vehicles, but possibly many more.

Alaa Makki, head of the parliament's education committee, urged the prime minister and the defense and interior ministers to respond rapidly, calling the abductions a "national catastrophe."

The mass kidnapping is the largest since about 50 people taken from the offices of a private security company in March. Their fate remains unknown.

Makki said the gunmen had a list of names of those to be taken and claimed to be on a mission from the government's anti-corruption body to check on security ahead of a planned visit by the U.S. ambassador. Those kidnapped included the institute's deputy general directors, employees, and visitors, he said.

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Police and witnesses said the gunmen, who numbered about 80, had closed off streets surrounding the institute, which is responsible for granting scholarships to Iraqi professors and students wishing to study abroad.

The facility appeared to be an easy target for the kidnappers, whose motives remain unknown. Police spokesman Maj. Mahir Hamad said four guards put up no resistance and were unharmed.

A source at the Interior Ministry said a local police chief in the Karradah district was taken into custody along with three of his officers to answer questions about the lack of police presence during the raid. The source said the policemen are not believed to have been a part of the kidnapping.

Witnesses including a visiting female professor said the gunmen forced men and women into separate rooms, handcuffed the men, and loaded them onto pickup trucks. She said the gunmen, some masked, wore blue camouflage uniforms of the type worn by police commandos.

Shiite militias and other illegal groups are known to wear stolen or fake police and army uniforms.

Brig. Abdul-Karim Khallaf, an Interior Ministry spokesman, told The Associated Press the three people released were found unharmed along eastern Baghdad's Palestine Street. Khallaf said the police chief of the Karradah neighborhood where the kidnappings occurred has been placed under investigation along with some of his officers.

The abductions come amid a series of killings and other attacks on Iraqi academics that is prompting thousands of professors and researchers to flee to neighboring countries to escape the country's lawlessness and sectarian hatred.

Recent weeks have seen a university dean and prominent Sunni geologist murdered, bringing the death toll among educators to at least 155 since the war began. The academics apparently were singled out for their relatively high public stature, vulnerability and known views on controversial issues in a climate of deepening Islamic fundamentalism.

Ali al-Adib, a Shiite lawmaker, demanded that U.S. troops be held responsible for the security lapse and said there was "a political goal behind this grave action."

Complete coverage is available in FOXNews.com's Iraq Center.

A spokesman for U.S. forces in Iraq said American troops were ready to help in the hunt for the kidnappers.

"If the reports are true, than this is a terrible crime and we will support all efforts by the Iraqi government to bring these criminals to justice," Lt. Col. Christopher Garver said.

The abductions came just hours after a U.S. assault on the northwest Baghdad Shiite district of Shula that drew strong condemnation from al-Adib and other Shiite members of parliament. Shula is a stronghold of radical anti-American Shiite cleric Muqtada al-Sadr, sponsor of one of Iraq's most powerful and feared militias, the Mahdi Army.

It also came a day after Gen. John Abizaid, head of the U.S. Central Command, confronted Prime Minister Nouri al-Maliki over how Iraqi forces would halt the raging violence.

The Associated Press contributed to this report.