NEW DELHI — Tens of thousands of Indians have declared a total of $9.5 billion in money that was either illegally obtained or not declared for tax purposes as part of a one-time opportunity to come clean under a government scheme, India’s finance minister said Saturday.

The declarations of the “black money” by 64,275 people came in a four-month window that ended Friday, allowing them to pay a tax, surcharge and penalty totaling 45 percent to avoid prosecution, Finance Minister Arun Jaitley said at a news conference.

Prime Minister Narendra Modi won elections in 2014 promising to curb corruption, the flow of black money abroad and lack of financial transparency.

The government has been facing opposition pressure to act since the April release of financial documents naming companies and individuals who may have dodged taxes by setting up shell companies and accounts through brokers based in Panama. The so-called “Panama Papers” include the names of about 500 Indians who have invested in offshore companies.

Jaitley said that a previous 1997 amnesty scheme had yielded $1.5 billion to the government.