“That timeline is the update I am aware of and is accurate,” one industry source said Thursday. The other said the information was “based on conversations with Treasury.”

Spokespeople for Treasury and the IRS could not be reached immediately for comment.

The payments are part of the massive coronavirus economic package enacted last month. They are aimed at giving a quick jolt to an economy ravaged by the pandemic, and there has been some discussion of a second round of payments if Congress takes up another rescue measure.

The IRS is working to get paper checks, beginning the first week of May, to the estimated 100 million Americans who don’t have direct deposit, the industry sources said. Some 5 million checks will be mailed weekly over 20 weeks.

Hoping to expedite more payments, the agency is expected to announce Friday that it will launch an online application later this month, called "Get My Payment," that will allow taxpayers who filed tax returns in 2018 or 2019 to submit direct deposit information if they didn't provide it on their returns.

A still unanswered question is how people without bank accounts, mostly with low incomes, will get access to their money once they get a check. Not all banks have agreed to accommodate non-customers, citing fraud concerns and social distancing guidelines from government health officials, one of the sources said.

That could force those people to turn to expensive check-cashing services.