"We need more guarantees in order to be sure Israel is completely committed to this resolution. We want to defend ourselves," Ghazi Hamad, a senior Hamas official, told Al Jazeera.
The UN text was the product of days of tortuous negotiations between top diplomats from the United States, Britain and France and Arab states.
Arab countries, many facing strong anti-Israeli sentiment at home, insisted the Security Council must issue a binding resolution that would force Israel to end its military campaign in the Gaza Strip immediately.
Israel had opposed the idea of a binding UN resolution.
The United States had backed its ally Israel but diplomats said it dropped its objections and agreed to go along with a cautiously worded text.
The US abstained from voting for the resolution, but Condoleezza Rice, the secretary of state, said the United States supported the contents of the resolution.
"The United States thought it important to see the outcomes of the Egyptian mediation efforts in order to see what this resolution might have been supporting," she said.
Riyad al Maliki, the Palestinian foreign minister, sounded sceptical after the passage of the resolution and said it might not bring about an immediate end to the violence in Gaza.
Speaking to Al Jazeera, he said it would be naive to expect that Israel would implement the ceasefire call immediately. He said he feared that the Israelis would expand their Gaza offensive in the next few days, to hit more targets before any truce comes into effect.
"I do believe that we will witness in the next two days vicious attacks against the Palestinian people and more Palestinians being killed even after such resolution has been passed," al Maliki said.
Al Jazeera's Ghida Fakhry, reporting from the UN, said the resolution was only a partial victory for Arab leaders, who succeeded in pushing through a resolution when the US and other nations were keener on issuing a non-binding "presidential statement".
|The Israeli assault on Gaza has killed 778 Palestinians and wounded thousands [AFP]
But they were also frustrated that an earlier Libya proposal was abandoned in favour for the US, UK and France resolution, our correspondent added.
Fakhry said it was "difficult to see how this [the resolution] is going to be enforced given the fact that the United States has decided to abstain thereby sending a clear signal that it will not do anything whatsoever to pressure its closest ally [Israel]".
Though the UN resolution is legally binding, it does not have any enforcement mechanism, and Israel has ignored dozens of UN resolutions over the years, our correspondent said.
It was also unclear whether Hamas would accept a text which does not mention the lifting of Israel's 18-month blockade on Gaza, which it has demanded, she added.