ISLAMABAD, Pakistan — A former president of Pakistan, Asif Ali Zardari, was indicted on Monday in a money laundering case, the latest legal action against him and one that his supporters say is part of a wider trend against politicians opposed to Prime Minister Imran Khan.

Mr. Zardari is the widower of former Prime Minister Benazir Bhutto, who was assassinated in 2007. He served as president from 2008 to 2013, and is currently a member of Parliament. He is also facing a raft of court cases.

He was arrested in June 2019 by anticorruption officials in a separate money laundering case and released on bail on medical grounds in December.

During the court hearing on Monday, a sister of Mr. Zardari, Faryal Talpur, and 13 other people were also indicted. Mr. Zardari and his sister denied the charges.

The charges against Mr. Zardari are related to money laundering through suspicious bank accounts and companies.

He and other opposition politicians have accused the Khan government of political victimization. Mr. Khan, who won the 2018 election on a strong anticorruption platform, denies the accusation. But critics say that Mr. Khan’s government, in collusion with Pakistan’s powerful military, is targeting the opposition in the guise of accountability.

When asked by court reporters for his comments on Monday’s indictment, Mr. Zardari replied with a verse in Urdu: “We have passed through such junctures earlier also.”

Before becoming president in 2008, Mr. Zardari spent 11 years in jail on corruption and murder charges. He was never convicted and has maintained his innocence, but allegations of corruption have followed him in his political career. The former president has remained active in politics, and his son, Bilawal Bhutto Zardari, is the chairman of the opposition Pakistan Peoples Party.

Chaudhry Manzoor Ahmed, another senior Pakistan Peoples Party figure,