WASHINGTON — The intercepted e-mail was alarmingly matter-of-fact for anyone worried about a new terror attack: “getting into U.S is no problem at all. thats what i do best.”

The Ghanaian man who wrote it is in prison, accused of smuggling East Africans into America via Latin America for economic reasons. But the government worries such operations also could be used to sneak terrorists into America now that passports and other travel documents have become harder to acquire and more difficult to fake.

Intelligence officials are focusing new attention on these networks that smuggle people from Djibouti, Eritrea, Somalia, and Sudan — known havens for terrorists, including Al Qaeda — according to an internal government assessment obtained by the Associated Press.

In the 12 months that ended last September 30, American officials caught 372 East Africans trying to get into the country, the assessment said. This is the most from these countries since the Homeland Security Department was formed in 2003. And 159 people from the same countries have been caught trying to enter since October 1 — including 138 from Eritrea, far more than any other country in the Horn of Africa.

“Any time we shut down a smuggling organization, there’s always somebody there to step in the place,” a unit chief of the Human Smuggling division at Immigration and Customs Enforcement, Scott Hatfield, said. “There’s always that potential that a terrorist might use an established network to come to the U.S.”

Authorities shut down one major East African pipeline in 2007, according to court documents reviewed by AP.

Mohammed Kamel Ibrahim, a 26-year-old Ghana citizen living in Mexico known as “Silk the Shocker,” wrote in an October 24, 2006, e-mail to an associate that he would have no problem smuggling somebody into America.

“i will pay my immigration friend 2 days before he comes so that he can be waiting for him immediately he gets out of the flight. that way there is no questioning,” Mr. Ibrahim wrote in the same e-mail.

All of this would cost $5,000. Mr. Ibrahim explained that if the client wanted to pay $2,000 less, he would have to answer questions from authorities himself and not benefit from the corrupt immigration official.

Mr. Ibrahim, the accused ringleader, and his partner, Sampson Lovelace Boateng, a 53-year-old Ghana citizen living in Belize, known as “Pastor,” were arrested last year in Mexico City and at the Miami airport, respectively. Their organization accounted for most of the pipeline from East Africa to America, officials say.

According to documents filed in the U.S. District Court for the District of Columbia, the smugglers had associates in Africa, typically corrupt officials. And they chose their routes based on which transit points employ easily bribed authorities.

Routes have included traveling from East Africa to Johannesburg, South Africa, and from Johannesburg to Sao Paulo, Brazil. East Africans also flew from Abu Dhabi, Dubai, or Rome to Bolivia, Brazil, Cuba, Mexico, and Venezuela in 2007, according to the intelligence assessment. In addition, the smugglers have access to fake and real Belizean, Bolivian, Chilean, Mexican, Peruvian, and South African visas.

In the Boateng and Ibrahim smuggling cases, people were stored in luggage compartments of buses for as long as 12 hours and driven to the American-Mexican border. The smugglers escorted clients as they walked across the border into the U.S. between official entry ports.

Messrs. Ibrahim and Boateng used international carriers DHL and Federal Express to deliver payments and travel documents.

On July 29, 2006, Mr. Ibrahim sent an e-mail to an unidentified associate: “i have a visa deal from ethiopia but it is a little bit expensive. I am currently in Belize to collect for some guys. i will get it in 3 days but it will cost 5000usd.”

The $5,000 would cover the visa and corrupt officials — the full smuggling package.

East Africans are mostly coming to America to find a better life because of job opportunities that don’t exist in their home countries.

One senior intelligence official said there’s little evidence yet of East Africans trying to cross into America to engage in terrorist activity. The official requested anonymity because the information in the assessment is not public.