Zambia's ex-president Rupiah Banda has been blocked from leaving the country but says he is unfazed by his "persecution".
Zambian immigration authorities on Friday prevented the 76-year-old from leaving the country for the third time in nearly two months, sparking widespread criticism from activists.
"No, no I am not heart broken by these persecutions and I have to be strong," Banda told the AFP news agency.
Banda, who is fighting corruption charges, was stopped from boarding a flight to South Africa despite a High Court order releasing his passport.
A raft of criminal charges were brought against him by his successor's administration led by Michael Sata which took office in September 2011.
Banda was stripped of diplomatic immunity in February and has been appearing in court on several corruption charges.
Banda, who has been accused of misappropriating more than $11m during his three years in office, was arrested and then later released on a bond, said Namukolo Kasumpa, a spokeswoman for the government's investigation team after Banda's diplomatic immunity was revoked.
He has maintained that the charges are politically motivated.
"At least I am happy that when I was president I did not do this to anybody," he said. "If I had done something like that my conscience would not be clear."
Banda accused the country's chief prosecutor Mutembo Nchito of harbouring great hatred against him.
The former head of state was set to fly to South Africa on a Friday morning flight for a conference.
His planned trip was marred by problems after a magistrate's court refused to return his passport, which he had to surrender after his re-arrest in April on corruption charges.
He later approached the High Court which released the travel document.
"We did all the airport formalities but surprisingly an immigration officer came and said he had instructions from above not to allow president Banda to travel," his press aide Kennedy Limwanya told AFP.
"We showed him a court order but he still said he could not allow us."
The government on Friday said it had slapped Banda with a formal travel ban.
"The investigations team has imposed travel embargoes against the former president for fear that he might interfere with the witnesses," said Home Affairs Minister Edgar Lungu.
Rights groups Friday strongly condemned the government's refusal to allow Banda's travels. The consortium of 11 organisations said Banda was not a flight risk.
Sata launched a raft of corruption cases against various officials of the former government, after taking over in 2011.