Israel has agreed to extend the ceasefire in Gaza by four hours.
But a Hamas official says the group is rejecting the extension.
Sami Abu Zuhri sent a text message to reporters Saturday, saying: ``No agreement to extending the calm for an additional four hours.''
Israel has set its own terms for the lull, saying it would continue demolishing Hamas military tunnels under the Gaza-Israel border.
According to the Israeli military, three rockets have been fired from Gaza at Israel despite the proposed extension.
The consequences of the rocket firing were not clear.
Residents of the war-torn region have been working fast to stock up on food and other necessities during a short 12-hour ceasefire that began at 1 am eastern Saturday.
Israeli forces and Hamas militants agreed to stop fighting after American Secretary of State John Kerry failed to broker a week-long truce.
Meantime, a Palestinian official says more than 1,000 Palestinians have been killed in the ongoing Gaza war.
Gaza health official Ashraf al-Kidra said that officials recovered more than 100 bodies alone on Saturday.
The higher death toll came as fighting lulled Saturday.
Israel's defence minister has warned he might soon expand the ground operation in Gaza "significantly.''