Angola's former vice president has failed to appear at a Portuguese court where he was scheduled to stand trial for corruption.

Portuguese prosecutors accuse Manuel Vicente, the African country's former deputy leader and one-time head of national oil company Sonangol, of corruption, money-laundering and forgery. They allege he paid a Portuguese magistrate to drop two investigations into alleged money-laundering and Angolan investments in Portugal.

Vicente's lawyer, Rui Patricio, told reporters outside the Lisbon court Monday that his client believes he has immunity from prosecution because of his previous status.

The case has strained relations between Angola and its former colonial ruler, with Angola's new president, Joao Lourenco, saying last month the accusation against Vicente was "offensive."

International human rights groups have long accused Angola's leadership of corruption.