Chelsea target Andre Villas-Boas has tendered his resignation as Porto coach, the Portuguese club have said.
They made the announcement in a statement to the Portuguese Securities Market Commission.
Villas-Boas, 33, has been linked with Chelsea in recent days following the sacking of Carlo Ancelotti in May.
Porto insisted on Monday that Villas-Boas could leave if a rival club paid £13.2m to activate a release clause in his contract.
"FC Porto was today notified of the intention of Andre Villas-Boas to resign from his contract with the club by triggering the release clause immediately," read a Porto statement.
"The contract will be terminated once the required amount is paid."