China said on Friday a deputy propaganda chief was under investigation for suspected corruption as President Xi Jinping wages a years-long campaign against graft.

Zhang Jianchun, a deputy head of the Central Propaganda Department, is being investigated for "suspected serious disciplinary and legal violations", the ruling Communist Party's anti-corruption agency said, using an official euphemism for alleged graft.

The one-sentence statement gave no details of Zhang's alleged offences.

He is one of the top officials in the highly secretive department that is charged with spreading the party's ideology as well as censoring China's tightly controlled media.

Zhang, 59, hails from eastern Shandong province and rose to prominence in a key party role in the capital Beijing, according to an official biography.

He entered the Organisation Department -- a powerful body directing nationwide party appointments -- in 2016, rising to deputy chief before taking on his most recent role in 2020.

Xi, China's most powerful leader in decades, has waged an unrelenting battle against deep-seated corruption since coming to power more than a decade ago.

Proponents say the campaign promotes clean governance, while critics say it serves as a vehicle for Xi to purge his political enemies.

It has in recent years become relatively rare for incumbent senior officials to fall afoul of the anti-graft drive.

The former deputy chief of the justice ministry came under investigation in April, but he had already relinquished his post last year.

The most senior official targeted under the campaign to date is Zhou Yongkang, Xi's powerful former security czar who was sentenced to life in prison in 2015 for bribery.

Lately, party graft-busters have trained their sights on the finance and banking sectors as well as state-owned enterprises.

Xu Zuo, a top executive at China Citic Group -- a vast state-backed investment conglomerate -- came under investigation this month for unspecified offences.

And Bai Tianhui, the former general manager at another huge state-backed asset management firm, Huarong, was sentenced to death in May after being found guilty of taking over 1.1 billion yuan ($151.8 million) in bribes.