The United States blamed Hamas for the breakdown of a ceasefire with Israeli forces Friday, accusing the Palestinian militant group of launching a "barbaric" attack to capture an Israeli soldier.
"This is an outrageous action and we look to the rest of the world to join us in condemning it," White House Deputy National Security Adviser Tony Blinken told MSNBC television.
The White House was reacting after Israel called an end to a three-day truce only hours after it began, accusing Hamas of attacking its troops, and expressing fears that a soldier had been captured.
Hamas for its part accused Israel of breaching the ceasefire, but Washington sided with its ally's version of events.
"The Israelis of course are reporting this morning that that ceasefire was broken," White House spokesman Josh Earnest told CNN.
"And that apparently Hamas individuals used the cover of a humanitarian ceasefire to attack Israeli soldiers and even to take one hostage. That would be a rather barbaric violation of the ceasefire."
Earlier, Gaza had enjoyed a brief respite after the humanitarian truce announced overnight by US Secretary of State John Kerry, the longest of several agreed since the conflict broke out on July 8.
Starting from 0500 GMT, it was supposed to mark a halt in the fighting that has killed nearly 1,500 on the Palestinian side, mostly civilians, and 63 Israeli soldiers and three civilians on the other.