(NewsNation) — Sen. Pete Ricketts, R-Neb., criticized President Joe Biden on Wednesday for threatening to withhold some weapons from Israel amid its conflict with Hamas militants in Gaza.

“Every time he makes any sort of criticism of what’s going on here and holds up these weapons, Hamas feels like their hand is strengthened, and they are not likely to negotiate,” Ricketts said on “The Hill on NewsNation.” “When President Biden says ‘ironclad,’ he doesn’t really mean it.”

Ricketts’ comments came as House Republicans prepare to force a vote Thursday on a resolution requiring the Biden administration to continue transferring weapons to Israel without preconditions during its battle with Hamas.

Ricketts accused Biden of not standing “ironclad” with Israel as promised and caving to political pressure from Democrats he characterized as “pro-Hamas.”

He contended Biden was defying Congress’ intent in passing aid to Israel and warned the president could make other U.S. allies doubt American reliability.

The Biden administration has told key lawmakers it plans to move forward on a new $1 billion sale of arms and ammunition to Israel, three congressional aides say.

It’s the first weapons shipment to Israel to be pushed ahead since the administration put another arms transfer, consisting of 3,500 bombs of up to 2,000 pounds each, on hold this month.

But the Biden administration, citing concern for civilian casualties in Gaza, has said it paused that bomb transfer to keep Israel from using those particular munitions in its offensive in the crowded southern Gaza city of Rafah.

The Associated Press contributed to this report.