FILE PHOTO: Pharmaceutical tablets and capsules are arranged on a table in a photo illustration shot September 18, 2013. REUTERS/Srdjan Zivulovic/Illustration/File Photo

WASHINGTON (Reuters) - Four Democratic U.S. senators introduced a bill on Thursday that would allow the government to block drug price increases that it decides are unjustified.

The bill sponsored by Senators Richard Blumenthal, Kamala Harris, Amy Klobuchar and Jeff Merkley, all Democrats, would allow the Department of Health and Human Services to prohibit drug price increases that it deems excessive.

Both Republicans and Democrats have put the issue of fast-rising drug prices - some for drugs like insulin that have been on the market for decades - on their agenda.

Representative Nancy Pelosi, who leads Democrats in the House of Representatives, has pledged to pursue an agenda next year that includes tackling the issue of high and rising prescription drug prices.

U.S. President Donald Trump has blasted drugmakers and healthcare “middlemen” for making prescription medicines unaffordable for Americans.