US Senator Lindsey Graham accused Hamas and Hezbollah of rearming during a visit to Israel on Sunday, and charged that the Palestinian group was also consolidating power in Gaza.
After two years of war between Israel and Hamas in the Palestinian territory, a fragile ceasefire has held since October, despite both sides trading accusations of violations.
A separate ceasefire between Israel and the Lebanese movement Hezbollah came into effect in November 2024 after more than a year of hostilities, though Israel continues to carry out strikes on Lebanese territory.
Israel has made dismantling the arsenals of both groups, allies of its arch-foe Iran, a key condition for any lasting peace.
"My impression is that Hamas is not disarming, they are rearming," Graham said in a video statement issued by Prime Minister Benjamin Netanyahu's office.
"It's my impression that they are trying to consolidate power (and) not give it up in Gaza."
The South Carolina Republican -- a staunch ally of US President Donald Trump, who helped broker the Gaza ceasefire -- added that he believed Hezbollah was likewise seeking to rearm itself.
"My impression is that Hezbollah is trying to make more weapons... That's not an acceptable outcome," he said.
"On both counts you are right," responded Netanyahu, praising the senator as a "great friend of Israel".
Graham's remarks came a day after mediators the United States, Qatar, Egypt and Türkiye urged both sides in the Gaza war to uphold the ceasefire.
The mediators are pressing for the implementation of the second phase of the truce, which would involve an Israeli withdrawal from Gaza, the establishment of an interim authority to govern the territory in place of Hamas and the deployment of an international stabilization force.
The second phase also envisages the demilitarization of Gaza, including the disarmament of Hamas.
Hamas has called on the mediators and Washington to stop Israeli "violations" of the ceasefire.
On Friday, six people, including two children, were killed in an Israeli bombing of a school serving as a shelter for displaced people, according to the civil defense agency in Gaza, which operates under the authority of Hamas.
The Lebanese government, meanwhile, has committed to disarming Hezbollah, starting in the country's south.
Israel, however, has questioned the effectiveness of the Lebanese military, and Hezbollah itself has repeatedly refused to lay down its weapons.
