The number-two US diplomat will head to Cairo and seek to extend beyond 72 hours a truce agreed by Israel and Hamas, a senior US official said Friday.

According to AFPDeputy Secretary of State William Burns - a veteran career diplomat frequently tasked with delicate missions - will travel to Egypt this weekend to take part in talks as part of the three-day truce that took effect Fridaythe official said.

The official said Burns would look to see if the two sides can extend the truce in the deadly conflict, especially as negotiators need time to travel to Cairo.

Israeli officials rarely meet during the Jewish Sabbath that starts at sundown on Friday.

"There is a hope for an extension because people have to travel and don't want to lose a whole day," a senior US official said on condition of anonymity in New Delhi, where Secretary of State John Kerry was on a visit.

But the official said an extension also depended on compromises during the talks, which aim to find a more lasting solution to the Gaza crisis.

"We obviously hope there will be (an extension of the ceasefire) and would encourage that, but obviously to do so there's got to be some sense of serious purpose on the table," the official said.

The US placed enormous pressure on Israel to accept a ceasefire since earlier this week, when Secretary of State John Kerry convened special talks in Paris with envoys from Turkey, Qatar, and Hamas in Gaza.

Despite vowing not to end the operation "until the job is done," Prime Minister Binyamin Netanyahu officially accepted the truce on Friday morning, following an announcement from Kerry and Hamas's alleged acceptance of the deal.