Cuba's top law enforcement official said Wednesday a crackdown on corruption that has given Cuba's international business community the jitters will continue and warned that no one was immune from prosecution.

Attorney General Dario Delgado, speaking at a conference on corruption, said the anti-corruption drive now underway in Cuba is systematic, permanent and necessary to strengthen the communist country's economy.

We will continue fighting until exhaustion, mercilessly, against all manifestations of corruption in the country, committed by foreigners or nationals, he said.

The crackdown began when President Raul Castro succeeded older brother Fidel Castro at the country's helm in 2008 and said widespread theft and graft had to be eliminated because it contributed to the Caribbean island's chronic economic woes.

It coincided with reforms to strengthen Cuba's socialist system. Dozens of Cubans have been jailed, including former government officials and top executives of state companies.

In recent months, executives of two Canadian trading companies and a British investment firm have been detained while investigators probe their finances, diplomatic and business sources said.

Last year, a Cuban joint venture with a Chilean firm was shut down and its Chilean executive Max Marambio sentenced in absentia to a long prison term for graft. Marambio, once a close friend of Fidel Castro's, stayed in Chile and denied the charges.

The legal actions have created unease among foreign businessmen, many of whom say they fear being unjustly accused of illicit acts. Those worries discourage foreign investment in Cuba at a time when the island needs it, they said.

Delgado, speaking to reporters after his speech, said the government had no problem with foreign businesses nor had the foreigners complained about the crackdown.

They have understood that (corruption) has to be eliminated. It is a very noxious practice, he said.

We will never stop defending the flags of honesty and dignity. It is our duty, Delgado said.

(Reporting by Nelson Acosta; Writing by Jeff Franks; Editing by Kevin Gray and Anthony Boadle)