The Iraqi government has temporarily detained more than 100 international workers in recent weeks over visas and paperwork, prompting some of their employers to ask U.S. Secretary of State Hillary Rodham Clinton to intervene, according to a trade group that represents contractors doing business here.

Most, if not all, of those detained have been released. But the detentions, which last from hours to days, are hampering the work of Iraq-based American diplomats, who rely on contractors, the International Stability Operations Association said.

“We want to ensure that you are aware of the seriousness of this issue,” the group said in a letter to Clinton on Sunday, “and the impact it is having on our members’ ability to support the transition and government programs in Iraq and ask your assistance in working with the Government of Iraq to reach a prompt solution.”

The letter’s author and the group’s president, Doug Brooks, said companies are having trouble driving in Iraq, and employees have been held at the airport in Baghdad over visas.

“The Government of Iraq has neither renewed 2011 visas nor issued new 2012 visas,” the group wrote in its letter to Clinton, adding, “Approved movements have been subject to stops, detentions, and confiscation of equipment without justification.

Brooks said the number of employees held in recent weeks is in the “low hundreds.”

“It’s completely hamstrung right now. No one can move. It’s been a nightmare,” Brooks said Monday.

“This is basically collateral damage from the infighting in the Iraqi government,” Brooks said. “The main reason seems to be bureaucratic incapacity.”

Brooks said three Iraqi ministries — defense, internal security and transportation — are apparently arguing among themselves over who should control the movement of foreign contractors. Oil and telecommunications companies also are facing problems, he said.

An Iraqi businessman, who works with international companies, expressed his frustration with the Iraqi government. “We are, on one side, trying to promote Iraq to get foreign investors, but from the other side, the government is creating all kinds of difficulties,” said the businessman, who asked not to identified so he could speak candidly about the government agencies he has to deal with.

“They just create rules overnight,” he said. “It’s a state of chaos.”

A spokesman for Prime Minister Nouri al-Maliki could not be reached for comment Monday.

The concerns of the companies, and the letter to Clinton, were earlier reported by The New York Times.

Michael McClellan, a spokesman for the U.S. Embassy in Baghdad, said embassy officials were not aware of any Americans currently being detained. Reached after business hours in Baghdad Monday, McClellan said he couldn’t immediately say how many Americans had been held. He declined to comment on the letter to Clinton, or on how contractors are being treated by the Iraqi government.

On Thursday, four U.S. Embassy workers were stopped and detained by Iraqi security forces for two hours.

And last week, the embassy issued a warning that people were being held for days over visas and paperwork. “Detentions often last 24-96 hours or more,” the U.S. Embassy said in a statement posted on its Web site. “The Embassy’s ability to respond to situations in which U.S. citizens are arrested or otherwise detained throughout Iraq is limited, including in and around Baghdad.”

Brooks said the problems extend to companies working with the U.S. government, private companies and on their own. Security companies in particular are not getting paperwork approved for routes. When armed guards can not travel in Iraq, that often means the companies that hire them also can not travel.

“While private organizations are often able to resolve low-level disputes and irregularities, this issue is beyond our ability to resolve and we need the assistance of the Department of State and the U.S. Embassy in Iraq,” Brooks wrote in his letter to Clinton.