Air strike kills 11 Palestinians
He added: "If this can be accomplished without a ramping up of military activity in Gaza, that is preferable. That's not just preferable for the people of Gaza, it's also preferable for Israelis because if Israeli troops are in Gaza they're much more at risk of incurring fatalities or being wounded," he said.
Mr Obama said he had been in regular contact with Egyptian and Turkish leaders - to secure their mediation in bring about a halt to rocket barrages by Hamas and other Islamist militants.
"We're going to have to see what kind of progress we can make in the next 24, 36, 48 hours," he added.
In other air raids today, two Gaza City media buildings were hit, witnesses said. Eight journalists were wounded and facilities belonging to Hamas's Al-Aqsa TV as well as Britain's Sky News were damaged.
An employee of the Beirut-based al Quds television station lost a leg in the attack, local medics said.
The Israeli military said the strike targeted a rooftop "transmission antenna used by Hamas to carry out terror activity", and that journalists in the building had effectively been used as human shields by Gaza's rulers.
Egyptian president Mohamed Mursi said in Cairo, as his security deputies sought to broker a truce with Hamas leaders, that "there are some indications that there is a possibility of a ceasefire soon, but we do not yet have firm guarantees".
Egypt has mediated previous ceasefire deals between Israel and Hamas, the latest of which has unravelled with the recent violence.
A Palestinian official told Reuters the discussions on a truce would continue in Cairo today, saying "there is hope", but that it was too early to say whether the efforts would succeed.
UN secretary-general Ban Ki-moon will be in Egypt tomorrow for talks with Mr Mursi, the foreign ministry in Cairo said. UN diplomats earlier said Mr Ban was expected in Israel and Egypt this week to push for an end to the fighting.
The head of the Arab League and a group of Arab foreign ministers will visit Gaza on Tuesday to show solidarity with the Palestinians, officials said in Cairo.
Asked on Israel Radio about progress in the Cairo talks, Silvan Shalom, one of Mr Netanyahu's deputies, said: "There are contacts, but they are currently far from being concluded."
Listing Israel's terms for ceasing fire, Moshe Yaalon, another deputy to the prime minister, wrote on Twitter: "If there is quiet in the south and no rockets and missiles are fired at Israel's citizens, nor terrorist attacks engineered from the Gaza Strip, we will not attack."
Israel's operation in the Gaza Strip has drawn some western support for what US and European leaders have called its right to self-defence, but there was also a growing number of appeals from them for an end to the hostilities.
British foreign minister William Hague said on Sky News that he and prime minister David Cameron "stressed to our Israeli counterparts that a ground invasion of Gaza would lose Israel a lot of the international support and sympathy that they have in this situation".