An Israeli security official said the transfer of aid into the territory is halted "until further notice," the first major test of the ceasefire.

Israel has reopened two crossings in Gaza, while the key Rafah crossing will stay closed to the movement of people until further notice.

By Nidal al-Mughrabi and Steven Scheer CAIRO/JERUSALEM (Reuters) -Israeli fire killed three people near a ceasefire line in Gaza on Monday, medics said, with U.S. envoys expected in Israel to try to push forward the fragile truce that faced its gravest test so far over the weekend.

Israel said it had begun "renewed enforcement of the ceasefire" Sunday after launching strikes in Gaza as it traded accusations with Hamas that each side had violated the fragile truce.

A round of violence on Sunday was short-lived, but analysts expect more tensions between Israel and Palestinian militants that will put the truce under strain.

Israel said it carried out air strikes on Gaza Oct. 19 after its troops were attacked, sending the ceasefire into uncertainty.

Detainees seek to return to their normal lives in Gaza after being freed from Israeli captivity, where some say they faced torture and beatings.

Israel has said it will resume enforcement of the ceasefire after launching air strikes on Gaza in response to what it called Hamas's "blatant violation".

Israel launched a wave of attacks on Gaza after accusing Palestinian militants of attacking its forces across cease-fire lines. Both sides say they are still committed to the truce.

The U.S. State Department says it has “credible reports” that Hamas could violate the ceasefire with an attack on Palestinian civilians in Gaza.

Israel and Hamas say they are committed to the ceasefire after clashes over the weekend. And, lawmakers not feeling the pressures of the government shutdown.