UNITED NATIONS - UN Secretary-General Ban Ki-moon on Monday called upon Israel to "do its part" to ensure a sustainable cease-fire with the Gaza-based Palestinian militants.

The secretary-general, who is in Vienna on Monday to visit Austria, made the appeal when he was speaking by telephone with Ehud Barak, the Israeli deputy prime minister and defense minister, said a readout from the UN Spokesperson's Office.

"The secretary-general said he was encouraged that the Gaza cease-fire was holding and urged Israel to do its part to ensure that the steps are taken to make the cease-fire sustainable," said the readout.

On Wednesday, Israel and Hamas, the Palestinian militant group in the Gaza Strip, reached a cease-fire agreement brokered by Egypt after the week-long clashes over Gaza.

The Israeli airstrikes killed 164 Palestinians, including 43 children, according to Gaza's Hamas-run health ministry. On the Israeli side, six were killed by rockets fired from Gaza.