A top al Qaeda lieutenant has met with leaders of a violent Salvadoran criminal gang with roots in Mexico and the United States — including a stronghold in the Washington area — in an effort by the terrorist network to seek help infiltrating the U.S.-Mexico border, law enforcement authorities said. Adnan G. El Shukrijumah, a key al Qaeda cell leader for whom the U.S. government has offered a $5 million reward, was spotted in July in Honduras meeting with leaders of El Salvador’s notorious Mara Salvatrucha gang, which immigration officials said has smuggled hundreds of Central and South Americans — mostly gang members — into the United States. Although they are actively involved in alien, drug and weapons smuggling, Mara Salvatrucha members in America also have been tied to numerous killings, robberies, burglaries, carjackings, extortions, rapes and aggravated assaults — including at least seven killings in Virginia and a machete attack on a 16-year-old in Alexandria that severely mutilated his hands. The Salvadoran gang, known to law enforcement authorities as MS-13 because many members identify themselves with tattoos of the number 13, is thought to have established a major smuggling center in Matamoros, Mexico, just south of Brownsville, Texas, from where it has arranged to bring illegal aliens from countries other than Mexico into the United States. Authorities said al Qaeda terrorists hope to take advantage of a lack of detention space within the Department of Homeland Security that has forced immigration officials to release non-Mexican illegal aliens back into the United States, rather than return them to their home countries. Less than 15 percent of those released appear for immigration hearings. Nearly 60,000 illegal aliens designated as other-than-Mexican, or OTMs, were detained last year along the U.S.-Mexico border. El Shukrijumah, born in Saudi Arabia but thought to be a Yemen national, was spotted in Tegucigalpa, Honduras, in July, having crossed the border illegally from Nicaragua after a stay in Panama. U.S. authorities said al Qaeda operatives have been in Tegucigalpa planning attacks against British, Spanish and U.S. embassies. Known to carry passports from Saudi Arabia, Trinidad, Guyana and Canada, El Shukrijumah had sought meetings with the Mara Salvatrucha gang leaders who control alien-smuggling routes through Mexico and into the United States. El Shukrijumah, 29, who authorities said was in Canada last year looking for nuclear material for a so-called “dirty bomb” and reportedly has family members in Guyana, was named in a March 2003 material-witness arrest warrant by federal prosecutors in Northern Virginia, where U.S. Attorney Paul J. McNulty said he is sought in connection with potential terrorist threats against the United States. A former southern Florida resident and pilot thought to have helped plan the September 11 attacks, El Shukrijumah was among seven suspected al Qaeda operatives identified in May by Attorney General John Ashcroft as being involved in plans to strike new targets in the United States. Citing “credible intelligence from multiple sources,” Mr. Ashcroft said at the time that El Shukrijumah posed “a clear and present danger to America.” In August, an FBI alert described him as “armed and dangerous” and a major threat to homeland security. Earlier this month, Mr. Ashcroft confirmed that U.S. border agents and inspectors had ramped up efforts to find El Shukrijumah amid reports that the al Qaeda leader was thought to be seeking entry routes into the United States along the U.S.-Mexico border. Mr. Ashcroft noted that increased enforcement efforts were under way in the wake of a rise of arrests of border jumpers from Afghanistan, Indonesia, Iran, Iraq, Jordan, Pakistan, the Philippines, Saudi Arabia and Syria. Authorities said Mara Salvatrucha gang members moved into the Los Angeles area in the 1980s and developed a reputation for being organized and extremely violent. The gang since has expanded into the Washington area, including Virginia and Maryland, and into Oregon, Alaska, Texas, Nevada, Utah, Oklahoma, Illinois, Michigan, New York, Georgia and Florida. More than 3,000 Mara Salvatrucha gang members are thought to be in the Washington area, with a major operation in Northern Virginia. Other gang centers, authorities said, include Montgomery and Prince George’s counties and the Hispanic neighborhoods of Washington. Mr. McNulty, whose office has prosecuted Mara Salvatrucha gang members, has described the organization as the “gang of greatest interest” to law enforcement authorities. He said gang members are recruited predominantly from Hispanic communities and typically among juveniles, some as young as 13. Recruits are “jumped” into the gang by being beaten by members while others count to 13, he said. Gang rules, he said, are indoctrinated into new recruits and ruthlessly enforced. Those who cooperate with law enforcement are given the “green light,” he said, meaning that the gang had approved their killing. In March, the Los Angeles City Attorney’s Office filed an injunction against Mara Salvatrucha, charging that the gang’s criminal activity constituted a “public nuisance” based on the number of killings, robberies and drug crimes. The injunction requires gang members, under public nuisance statutes, to follow curfew rules and regulations and prohibits them from associating, driving or appearing together in designated areas of the city.