President Trump stops to talk to reporters Friday as he make his way to board the Marine One helicopter on the South Lawn of the White House. (Jabin Botsford/The Washington Post)

President Trump urged the Republican-led Senate on Monday to pass legislation intended to crack down on shipments of illicit fentanyl through the international postal system, writing on Twitter: “No more delay!”

Leaders from both chambers announced a bipartisan agreement in June on the Synthetics Trafficking and Overdose Prevention Act, which the House passed shortly thereafter. The Senate has yet to act on the bill, as Majority Leader Mitch McConnell (R-Ky.) has focused on confirming federal judges and passing appropriations bills.

“It is outrageous that Poisonous Synthetic Heroin Fentanyl comes pouring into the U.S. Postal System from China,” Trump wrote on Twitter. “We can, and must, END THIS NOW! The Senate should pass the STOP ACT — and firmly STOP this poison from killing our children and destroying our country. No more delay!”

The president’s tweet did not mention McConnell or explicitly place blame for what he considers to be a delay.

Some health-care industry insiders have accused McConnell of delaying a vote on legislation tackling the opioid crisis because passage would give vulnerable red-state Democrats an accomplishment to campaign on back home. His office has denied this and predicted quick action.

On Tuesday, McConnell told reporters at the Capitol that Sen. Lamar Alexander (R-Tenn.) and other Republicans in the chamber are working on reaching an agreement on the timing of the legislation and that it would probably come up for a vote in the fall.

“Another priority for the post-Labor Day weekend is an opioid bill,” McConnell said. He added: “We’ve appropriated a lot of money, we need to now pass a bill to direct the spending of that money. And opioids remains a very big bipartisan priority here in the Senate.”

At least one prominent Senate Republican praised Trump on Monday for calling for swift action on the measure.

In a statement, Sen. Rob Portman (R-Ohio) commended Trump “for leading the charge to combat the opioid epidemic and calling for the Senate to pass the bipartisan STOP Act.”

“This bipartisan legislation passed the House overwhelmingly in June, and it’s long past time for the Senate to pass this bill so it can become law and begin making a difference,” Portman said.

Kellyanne Conway, counselor to the president, also hailed Trump’s remarks on the subject.

“Fentanyl was responsible for nearly 30,000 deaths in the US last year. Many Americans don’t know it can be an instant killer when laced into pills, marijuana,” Conway tweeted. “Thank you @realDonaldTrump for showing courage & resolve to keep the poison out of our communities & out of our kids.”

Among other provisions, the STOP Act would require the Postal Service to install the same tracking system used by private shippers such as FedEx to attempt to curb shipments of fentanyl.

A congressional report released this year found that online sellers of fentanyl prefer to ship it through the Postal Service rather than private shippers because they perceive less risk that packages will be seized by U.S. Customs and Border Protection.

The Centers for Disease Control and Prevention reported preliminary estimates that more than 72,000 people died of drug overdoses in the United States last year, an increase of 9.5 percent from the year before. One reason for the increase was illicit and deadly fentanyl, which has increasingly been cut into heroin and cocaine.

At a Cabinet meeting last week, Trump accused China of “sending that garbage and killing our people,” adding: “It’s almost a form of warfare.”