A member of Gambia's main opposition has died in state custody, the United Democratic Party said Monday, in the second such case in five months.

Local party official Ebrima Solo Krummah, who was detained in May during a rare protest, died after being hospitalised and undergoing an operation Friday, the party said.

"We went to the mortuary... and confirmed the death of Ebrima Solo Krummah," party president Dembo Bojang told AFP.

The party will make sure "a postmortem is conducted by the doctors before his body is handed over to the family for burial," he added.

Neither activists nor Krummah's family were given any information about his medical condition and were "repeatedly denied access to him throughout his stay in state custody," the UDP said in a statement.

The party blamed the government for the death, accusing them of "intentionally inflicting bodily harm and then steadfastly withhold urgent lifesaving medical interventions."

Prominent opposition activist Solo Sandeng died in custody this April, triggering protests at which UDP leader Ousainou Darboe was arrested.

Darboe was sentenced to three years in jail last month over that demonstration.

The US State Department said it was "deeply concerned" by the most recent reported death. 

"We remain troubled by reports of the Gambian government's continued mistreatment of detained opposition figures, as evidenced by recent deaths and allegations of torture," deputy spokesman Mark Toner said. 

Toner called for an independent investigation into the deaths.

President Yahya Jammeh, who came to power in a 1994 coup, rules The Gambia with an iron fist.

His regime is regularly accused by rights groups of forcibly disappearing opponents.

He has blasted the UN and Amnesty International for demanding an investigation into Sandeng's death, saying they could "go to hell".

Source: AFP