House Speaker Mike Johnson (R-LA) accused President Joe Biden of failing to take adequate action to help free the remaining American hostages being held in Gaza in a new letter to the president sent Wednesday morning.

“I write today to express grave concern that your administration is not taking sufficient steps to ensure the release of American hostages who are detained by Hamas terrorists in Gaza,” Johnson wrote.

He accused Biden of failing to “resolutely support Israel in its military objectives to eliminate Hamas,” which Johnson said has “made it harder to facilitate the release of those being detained.”

The letter alludes to reports that the administration has ceased to use emergency powers to accelerate the delivery of weapons to Israel and is otherwise delaying arms shipments. In the letter, Johnson urged Biden to “restore the use of emergency authorities to ensure Israel has everything it needs immediately to defeat these threats and restore security.”

The House speaker, invoking the families of the hostages, further called on Biden to “leverage all American options and influence to support Israel in bringing these hostages home,” as well as “put maximum pressure on Hamas and its enablers.”

The administration has been pushing for Hamas to accept a cease-fire laid out by Biden and approved by Israel. But Hamas has rejected that agreement, officials say, highlighting that Yahya Sinwar, the Hamas leader in Gaza, has not been responsive to international pressure.

Johnson alleged that “American families feel betrayed by a President who is allowing their loved ones and other hostages to languish.” The families of American hostages have largely spoken positively of Biden and his work to free their loved ones.

The speaker accused Biden of being more focused on “attempting to micromanage Israel” than on the hostages’ release, and alleged that administration decisions have “undercut” release efforts, “weakened the U.S.-Israel relationship, eroded America’s ability to deter our enemies” and undermined Israel.

Johnson called the administration’s actions “unconscionable [and] unacceptable.”

He asked the administration to brief Congress by July 10 about the administration’s strategy for freeing the hostages and supporting Israel against Hamas and Hezbollah.