Mexican police have arrested a US citizen accused of being a key figure in a major drug cartel based in the border city of Tijuana.
Gustavo Rivera Martinez was arrested with several others
Gustavo Rivera Martinez was responsible for the logistics of smuggling drugs to the US and laundering the proceeds, Mexico's interior minister said.
He is wanted by the FBI and the US Drug Enforcement Agency which offered a $2m (£1m) reward for his capture.
Mr Rivera Martinez would be sent back immediately to the US, officials said.
"This individual is one of the criminals most sought after by the DEA and FBI," said Mexican Interior Secretary Juan Camilo Mourino.
Mr Rivera Martinez was arrested in the state of Baja California Sur together with several other suspects.
He had been a fugitive from US justice since 2002.
Mexican officials said Mr Rivera Martinez was a key figure in the Tijuana cartel and close to Enedina Arellano Felix, the latest member of the Arellano Felix family to head the drugs ring.
The Arellano Felix cartel, based across the US border from San Diego, rose to prominence in the 1980s.
It paid millions of dollars in bribes to local law enforcement officers and was blamed for increasing violence, including the murder of informants and rival traffickers.
Much of the group's activities centred on smuggling Colombian cocaine through Mexico to California.
Correspondents say this latest arrest will be seen as a further blow to the cartel whose power has been undermined by a concerted drive against its leaders.
One of its founders, Francisco Javier Arellano Felix, was sentenced to life in prison by a US court last year after pleading guilty to running the cartel.
But as the Tijuana cartel's influence has waned, other drugs gangs have tried to move in on its turf.
Drug-related violence has become a serious issue across Mexico and since taking office in December 2006, President Felipe Calderon has sent some 25,000 soldiers and federal police to key areas to tackle the drug-traffickers.