FACTBOX: U.S. responses to Israel's Gaza attacks

(Reuters) - Israel's attacks on Gaza three weeks before Barack Obama becomes U.S. president pose an unexpected challenge for a man who has promised to work for Middle East peace from his first day in office.

Questions have emerged over the timing of the attacks during a period of transition in the United States and over how Obama might respond as president and Hillary Clinton as his secretary of state.

Such questions often arise because Washington traditionally plays the role of broker in any Middle East peace moves.

HOW HAS THE UNITED STATES RESPONDED?

The Bush administration, due to hand over to Obama on January 20, put the onus on Hamas, the Islamists in charge of Gaza, to prevent more violence. It did not demand an end to Israeli attacks but urged all concerned to protect innocent lives.

Steven Cook, senior fellow for Middle East studies at the Council on Foreign Relations, said: "There's little that the United States can do to call the Israelis off. The Bush administration and the incoming administration are going to be hard pressed to find something productive that they can do immediately."

WHAT DID THE UNITED NATIONS SAY?

The strikes against Hamas have killed hundreds of Palestinians, prompting a U.N. Security Council call for a ceasefire. But an Israeli official said Israel was feeling little international pressure to halt its attacks.

WHAT HAS OBAMA SAID?

Obama's team has avoided policy statements while George W. Bush is in power. Adviser David Axelrod said on CBS's "Face the Nation" on Sunday: "There's only one president who can speak for America at a time. And that president now is George Bush."

Bush's secretary of state, Condoleezza Rice, spoke to Obama by phone. "They have a good working relationship," Axelrod told the news program. "The calls are largely in the area of fact-finding for him."

WHAT MIGHT OBAMA DO?

In the CBS interview, Axelrod recalled that when then-candidate Obama was in the southern Israeli town of Sderot in July, he voiced understanding for Israel's urge to try to put an end to attacks on Sderot from Gaza.

On the broader issue of Middle East peace, Obama promised to engage in Israeli-Palestinian peacemaking from the start but has yet to propose a policy shift that might rescue a two-state solution from oblivion.

"My goal is to make sure that we work, starting from the minute I'm sworn into office, to try to find some breakthroughs," Obama said in July. But he added it was unrealistic to expect him to "suddenly snap his fingers and bring about peace."

WHAT ELSE FACTORS INTO PEACE MOVES?