Actor Sean Penn said Monday he has "nothin' to hide" about his clandestine visit to Mexican drug lord Joaquin (El Chapo) Guzman, dismissing criticism over his interview with the fugitive who was captured last Friday.

In a brief email exchange with The Associated Press, Penn was asked about images published by local news media that indicate Mexican authorities were closely monitoring him and actress Kate del Castillo ahead of their October visit with Guzman.

"I've got nothin' to hide," he wrote.

Penn shrugged off a suggestion that he was "taking hits" for agreeing to submit the story to Guzman prior to publication of the story by Rolling Stone magazine.

"No, you're reading hits," he said.

Agrees journalists envious of story

There are quite a few envious journalists, the AP reporter commented. "True dat," Penn replied.

Guzman was captured Friday, more than three months after meeting Penn on Oct. 2 meeting and six months after escaping from prison.

Penn did not respond directly to questions on whether it was appropriate for him to submit his story to Guzman for approval in advance of publication, though he said in the article that Guzman requested no changes.

Mexican officials have said that Guzman's contacts with Penn and del Castillo helped them track down the fugitive and they raided his hideout a few days after they met. Guzman evaded authorities then, but was finally captured Friday in the Pacific coast state of Sinaloa.

A Mexican federal law enforcement official, speaking on condition of anonymity because he was not permitted to comment on the issue, told the Associated Press the Penn interview led authorities to Guzman in the area of Tamazula, a rural part of Durango state.

Penn wrote in the article of elaborate security precautions, including switching phones. But as he flew to Mexico for the meeting, he wrote "I see no spying eyes, but I assume they are there."

He may not have known how close those eyes were. They were apparently already following del Castillo based on contacts with Guzman lawyers.

Tracking of Penn's movements

The Mexican newspaper El Universal published 10 photographs Monday that appeared to show Penn being monitored as he arrived in Mexico.

The photographs that appear to show Penn and del Castillo arriving at an airport, then at a hotel, and greeting the men who apparently took them to a small airstrip, from which they flew to the jungle camp to meet Guzman.

The newspaper said the photos are part of a Mexican government intelligence file that it obtained. It is not clear which may have been frame grabs from surveillance videos,

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Sean Penn has long been able to arrange meetings with prominent politicians, past and president, Here, Penn appears with former Russian President Mikhail Gorbachev, left, while the actor speaks to students at the Frederick Von Steuben Metropolitan Science Center in Chicago on April 23, 2012. (Jeff Haynes/Reuters)

The account says agents were aware of and following del Castillo's contacts with Guzman's lawyers since at least June. Del Castillo has not commented.

Monday evening, Mexican President Enrique Pena Nieto referenced Guzman's capture in a short new year's message to the nation.

"The detention of the world's most wanted criminal is a credit to the coordination of our institutions in favor of security and the rule of law," Pena Nieto said. "With this action, 98 of the 122 most dangerous criminals no longer present a threat to society and we are going for all of them."

Mexico has begun the process of extraditing Guzman to the United States, but that process will probably take "one year or longer," the head of Mexico's extradition office, Manuel Merino, told Radio Formula on Monday. He said the process had lasted as long as six years, in one case because of legal challenges.

In the meantime, Guzman was being held at the same prison from which he escaped through a tunnel in July. But a Mexican security official said he is being held in a different cell. The official was not authorized to be quoted by name.

Both his original cell and the mile-long tunnel he had built have been "made unusable," the official said, without specifying how.

APTOPIX Mexico Drug Lord

Mexican drug lord Joaquin (El Chapo) Guzman, right, is shown being escorted by soldiers and marines to a waiting helicopter on Jan. 8 after his capture. (Marco Ugarte/The Associated Press)

The prison is now ringed by soldiers, marines and federal police. Some of the soldiers are riding in armoured personnel carriers.

Guzman's powerful Sinaloa cartel smuggles multi-ton shipments of cocaine and marijuana as well as manufacturing and transporting methamphetamines and heroin, mostly to the U.S. He is wanted in various U.S. states and his July escape deeply embarrassed the government of President Enrique Pena Nieto and strained ties between the countries.

Guzman's attorney Juan Pablo Badillo has said the defence has already filed six motions to challenge extradition requests.

Badillo said that his client shouldn't be extradited to the U.S. because "our country must respect national sovereignty, the sovereignty of its institutions to impart justice."