US senators on Monday demanded Meta address reports that its Facebook and Instagram social networks have been censoring information about how to legally get an abortion.

Democratic senators Amy Klobuchar and Elizabeth Warren gave Meta until July 15 to answer questions including how many posts about abortion have been removed since the US Supreme Court overturned a long-standing right to such medical care.

"Reports indicate that multiple posts providing accurate information about how to legally access abortion services were removed, often within minutes after the information was posted," the senators said in a letter to the chiefs of Meta and Instagram.

In response to a request for comment, Meta referred AFP to a tweet by spokesman Andy Stone saying that while attempts to provide or procure pharmaceuticals are banned by content policy, posts discussing access to medications are allowed.

"We've discovered some instances of incorrect enforcement and are correcting these," Stone said.

A Meta glitch had also resulted in posts about abortion and other topics being accidentally veiled by banners marking them as "sensitive" material, according to the tech giant.

The senators want to know what measures are used to flag abortion-related posts, according to a copy of a letter sent to Meta chief Mark Zuckerberg and Instagram boss Adam Mosseri.

"As a result of the court's decision, it is more important than ever that social media platforms not censor truthful posts about abortion," the senators said in the letter.

In a first, a pharmaceutical company applied Monday for US approval to make its birth control pill available over-the-counter.

HRA Pharma, a subsidiary of Perrigo, said in a statement it was seeking the switch away from prescription-only for its product Opill, a progestin-only daily birth control pill -- also referred to as a mini pill or non-estrogen pill.

The application will now be reviewed by the Food and Drug Administration, a process that would normally take around a year to complete.