MEXICO CITY (REUTERS) - Mexican security forces on Tuesday (May 2) arrested accused drug kingpin Damaso Lopez, believed to be locked in a bloody struggle for control of the Sinaloa Cartel against the sons of its captured leader Joaquin "El Chapo" Guzman.

The attorney-general's office announced that its agents with the help of the army had captured Lopez, one of the top-ranking figures in the world's most successful drug cartel, which has been destabilized by "El Chapo's" extradition in January to the United States.

Lopez, nicknamed "The Graduate," was captured in an apartment in a middle-class Mexico City neighbourhood in the early hours of Tuesday, a few weeks after a video emerged of him eating at a Mexico City restaurant.

He was held at the apartment with a heavy army presence outside the building before being sped in a convoy of white vehicles through the city to a unit of the attorney-general's office, live TV footage showed.

Lopez is himself a former security official who Mexican officials say played a role in orchestrating Guzman's first escape from prison in 2001, before joining the cartel.

Guzman, who broke out twice from prison in Mexico, was recaptured for the last time in January 2016. One of the world's most wanted drug lords, he was extradited to the United States to face charges there on Jan 19, the eve of Donald Trump's inauguration as US president.

Trump has vowed to break the power of transnational drug cartels and said that his planned wall on the US-Mexico border would stem the flow of drugs into the United States. He has issued executive orders that aim to improve coordination between US law enforcement agencies and their foreign partners.

Guzman's latest imprisonment triggered a violent power struggle that has led to daylight gunbattles involving truck-mounted machine guns in the northwestern state of Sinaloa, with Mexican officials attributing the bloodshed to a tussle between Lopez and the former leader's sons.