Somali refugees in Minnesota have sent at least $75 million to East Africa, using banks to make large wire transfers that have drawn the attention of federal investigators, according to people familiar with the inquiry.

Most of the money -- sent by individuals in chunks of $100 to $600 a month -- is humanitarian aid for people caught in the violence of a country ruled by warring clans, according to interviews with Somalis in the Twin Cities area. But some also say that an organized collection system exists in Minnesota to pressure Somalis into contributing small sums for guns and clan-based militias back home.

An average of $2 million a month now leaves Minnesota for Middle Eastern banks to be distributed in Somalia and in refugee camps in neighboring African countries, Somalis and sources familiar with the investigation said. They say the wire transfers have been as high as nearly $4 million a month.

Some Somalis point to a Muslim culture of giving and say they feel obligated to help family and friends left behind. To raise the money, many work multiple jobs and live in crammed apartments.

The money flow began at least four years ago, sources said, in amounts small enough not to attract immediate attention. Minneapolis police began investigating early last year, but decided to let federal authorities handle it.

The investigation by the FBI, the Immigration and Naturalization Service (INS) and the Internal Revenue Service (IRS) centers on how the money is collected, where it goes and who donates. The investigation is said to be in an early stage.

U.S. authorities are concerned that some of the money may have been used for military purposes in the war-ravaged country.

Contributions in support of a terrorist organization are illegal if the donor knowingly gives money for a subversive purpose, said Mark Cangemi, head of INS investigations in Minnesota, Iowa and the Dakotas. But that can be difficult to prove, he said.

The INS acknowledged an inquiry but declined to discuss specifics. The FBI and the IRS declined to comment. The investigation into how the money is collected and where it goes hasn't led to charges.

Most of the money is transferred abroad through banks. Two Twin Cities banks have acknowledged discussions with federal authorities about the money pipeline.

Bank accounts of several Somali money-transfer businesses have been used to hold money raised in Minnesota. Frequent, large transfers have been made, nearly emptying the bank accounts, according to the money-transfer firms.

Somalia recently established its first government since the 1991 overthrow of dictator Muhammad Siad Barre. War and famine in the 1990s left its people poor and homeless. Hundreds of thousands of Somalis still live in refugee camps.

"Imagine a people with no central government. It is chaos," said Mohamed Ali Nor, owner of Dahab-shil Inc., a Somali money-transfer business in Minneapolis. "Imagine no schools, no employment, no jobs. And if you try to farm, your stuff is dying or taken and looted. People are starving, so you help your mom, your dad. You should help the family."

But Abdi Samatar, an author of two books and many articles on Somali culture, said not all of the money is humanitarian aid. "Some people are sending money to warlords," he said. "That's a human rights violation of major proportions, and it's a criminal act, in my opinion."

Collections in Minnesota for warlords in Somalia have fueled "the very violence that has brought them here in the first place seeking refuge," said Samatar, who grew up in Somalia and is a geography professor at the University of Minnesota.

"It's absolute madness," he said.

He and other Somalis say pressure to give money to warlords has lessened in recent months. Somalian President Abdiqasim Salad Hassan, who took office in August, hopes to restore security after a decade of anarchy. But as recently as September, a clash of heavily armed Somali militias left 20 dead and 18 wounded.

The collectors