Israeli officials say they are considering a 48-hour halt to their offensive in the Gaza Strip - after four days of air strikes against the Palestinian militant group Hamas.  The strikes have killed more than 370 people, mostly Hamas militants.  Hamas has fired rockets into Israel, killing at least four people.  Countries around the world, including the United States, are calling for a cease-fire.

The Israeli military carried out more air strikes on Tuesday, killing several people and destroying Hamas government buildings, including one at an Islamic university.  Israeli troops are massing along the Israel-Gaza border, possibly preparing a ground offensive.

Palestinian militants fired a rocket deeper into Israel for the first time, striking the city of Beersheba.

Israeli Defense Minister Ehud Barak says Israel will do whatever it takes to put an end to what he calls Hamas's campaign of terror.

In Washington, Israel's U.S. Ambassador, Sallai Meridor, blamed Hamas for breaking a six month cease-fire and said his country wants peace.  He blamed Iran for supporting Hamas.

"It's guided by Iran," said Sallai Meridor. "It's funded largely by Iran.  It's trained by Iran."

Israeli leaders say they are considering a short-term truce to allow aid into Gaza.  
Ambassador Meridor says Israel has already brought in trucks of food.

"We are letting in a lot of humanitarian aid under these terrible circumstances, under fire, and go through the passage and get into Gaza," he said.

But a boat carrying international peace activists and medical aid was denied entry into Gaza on Tuesday.  The boat was turned away by an Israeli naval vessel.

Anger at the Israeli offensive has triggered protests across the Middle East.  Pro-Palestinians in the U.S. also held protests in Washington and New York.  Activist Riham Barghouti.

"We want to raise awareness among the Americans here so they can understand what is going on, and also to call for an end to U.S. support, because it is U.S. planes that are bombing Gaza," said Riham Barghouti.

The United States is calling for a durable and sustainable cease-fire by both Israel and Hamas.  European Union foreign ministers also are calling for both sides to stop the fighting.