QUITO, July 09 (BSS/AFP) - The imprisoned mayor of Ecuador's most populous city and main commercial port refused surgery Wednesday, Interior Minister John Reimberg said, despite claims that he is suffering from heart and gallbladder conditions.

Aquiles Alvarez -- a vocal critic of right-wing president Daniel Noboa -- is in prison after a February arrest over alleged money laundering.

Alvarez was flown by helicopter to a private clinic for testing, but later "rejected the treatment and the gallbladder surgery," according to Reimberg.

A lawyer for the mayor, Julio Cesar Cueva, said that "the decision had been made for the mayor to undergo surgery, but it will not be today."

Both the minister and the lawyer said the mayor was back in El Encuentro prison, a mega-security facility in neighboring Santa Elena province.

Alvarez, an ally of opposition socialist ex-president Rafael Correa, has criticized Noboa's war on gangs, including his decision to send soldiers into the streets, and has not ruled out running for president.

After his arrest, prosecutors released pictures showing bags of money as well as computers and mobile phones.

In July of last year he was fitted with an electronic ankle monitor while being investigated in a separate case, for alleged fuel trafficking.

Alvarez denies all the allegations against him, arguing that they are an attempt to disqualify him from running for reelection next year.

Human rights groups and relatives of inmates have questioned the management of Ecuador's prison system.

Five mayors from different Ecuadoran cities have been arrested for alleged corruption ahead of November local elections, which have been clouded by the suspension of political parties opposed to the government.

Guayaquil, a city of nearly three million people, is the nexus of Ecuador's ballooning drug trade.

Its port has become a major transit point for drug smugglers trafficking cocaine from neighboring Colombia and Peru en route to the United States and Europe.