WASHINGTON (AP) — President Donald Trump signed an order on Monday. It gives drug companies 30 days to lower the price of prescription drugs in the U.S. by choice. If they don't, they will face new rules later about what the government will pay.

The order tells the health department, led by Robert F. Kennedy Jr., to negotiate new drug prices next month. If they can't agree on prices, Kennedy must create a new rule. This rule would base U.S. drug prices on the lower prices paid in other countries.

"We will make things equal," Trump said at a press conference on Monday morning. "We will all pay the same amount. We will pay what people in Europe pay."

It's not clear how the Republican president's order will affect millions of Americans with private health insurance. The government has the most power to control the price of medicines for Medicare and Medicaid.

Trump talked about possible savings on the cost of drugs. This happened right after the Republican House suggested cutting Medicaid by $880 billion.

The organization representing America's main drug companies quickly opposed Trump's decision, saying it was not good for patients. These companies have often said that if their profits are reduced, it could affect the research they do to create new medicines.

Stephen J. Ubl, the head of PhRMA, said that using prices from other countries would be bad for American patients and workers. He explained that it would lead to fewer treatments and cures, and could put at risk the large amount of money their companies plan to spend in America.

Trump's idea to make Medicare pay less for some medicines, like other countries do, has caused arguments since he first suggested it.

That limited order had problems, as a court stopped it from starting under President Joe Biden's government. The drug companies said Trump's 2020 try would give other countries an advantage in choosing the cost of medicines in the U.S.

During a long speech at the White House on Monday, Trump often supported drug companies. He said that other countries were responsible for the high cost of medicines in America. The president was with several important people, including Kennedy, Dr. Mehmet Oz from Medicare and Medicaid Services, Dr. Marty Makary from the Food and Drug Administration, and Jay Bhattacharya, the head of the National Institutes of Health.

However, he warned the companies that he might start government investigations into their actions and let more imported medicines from other countries come into the U.S.

Trump stated that drug companies earn most of their money in America, adding that this is not positive.

Over the weekend, Trump talked a lot about the announcement, saying in one message that his plan could save "TRILLIONS OF DOLLARS."

But on Monday, the White House did not say exactly how much money they expect to save.

The health department's main leaders will meet with drug company bosses in the next month. They will suggest new drug prices based on what other countries pay, Oz said on Monday.

According to Rachel Sachs, a health law expert at Washington University, Americans probably won't see drug prices go down fast because of the order.

Sachs said the plan seems to be to ask companies to lower their prices by choice to a level that is not yet known. He added that if they don't lower their prices enough, the government will take other steps that will take a long time, and some of these might lower drug prices later on.

The health department has the main power to change drug prices for Medicare and Medicaid by making rules, but its power is limited. In 2022, a new law was passed allowing Medicare to discuss and agree on lower prices for some drugs starting in 2026. Before this law, Medicare paid whatever the drug companies asked. Drug companies went to court to try and stop this law, but they did not succeed.

It's even harder for the agency to change the price of medicines for millions of Americans who have private insurance.

The US often spends more on medicines than other big, rich countries. This has annoyed both major political parties for a long time, but they haven't been able to find a permanent solution in Congress.

When Trump started his first time as president, he said that drug companies were "getting away with murder." He also complained that other countries that control medicine prices were taking advantage of Americans.

Before the announcement, Trump criticized drug companies on social media, saying they claimed research costs were paid only by Americans.

He said that drug companies try hard to influence politicians. He also said that money for campaigns "can do a lot, but not with me or the Republican Party."

"We will do what is right," he wrote.

Some large drug companies did well on the stock market on Monday morning. For example, Merck, which earned $64.2 billion last year, including from its cancer medicine Keytruda, saw its shares go up by 3.9%. Pfizer, another big drug company with revenues of $63.6 billion this year, increased by 2.5%, and Gilead Sciences went up by 5.8%.