BEIJING -- Former vice mayor of Shanghai Ai Baojun is under investigation for alleged bribe-taking, the Supreme People's Procuratorate (SPP) announced on Friday.

Ai has been put under "coercive measures," which may include summons by force, bail, residential surveillance, detention and arrest. The SPP did not specify what measures had been taken against him.

The Communist Party of China (CPC) Central Commission for Discipline Inspection (CCDI) announced its investigation into Ai in November.

Ai was expelled from the CPC and removed from office for "serious discipline offenses" including confronting the investigation, accepting bribes, trading power for sex and embezzling public assets, according to a CCDI announcement on Jan. 19.