A senior advisor to the prime minister of Lebanon decried Israel's bombing of Qana, Lebanon, as a "war crime.
"This can only create more extremism, more hatred," said the advisor, Mohamad Chatah, in an exclusive appearance on "This Week with George Stephanopoulos." He then called for "an immediate ceasefire."
The Israeli air strike on Qana killed dozens of civilians, more than half of them women and children.
In a press conference following the Qana bombing, Secretary of State Condoleezza Rice said, "I will continue to work and work and work. That is what we can do. If there is any way humanly [possible] to accelerate our efforts I would do it, but we are already doing really what is at the human limitation to try and get to an end in this conflict."
Rice, continuing shuttle diplomacy in Jerusalem, cancelled plans to travel to Beirut, and said it is "time for a ceasefire" in the wake of the 19-day struggle's latest violence.
Also appearing on "This Week", Undersecretary of State Nicholas Burns and Daniel Ayalon, the Israeli ambassador to the United States, rejected Shattah's description of the bombing as a war crime.
"The United States does not believe that what has happened over the last two weeks constitutes a war crime," Burns said.
Ayalon laid blame on the Hezbollah, the militant group that began the conflict without the knowledge of the Lebanese government nearly three weeks ago.
"It was a war crime committed by the Hezbollah," Ayalon said, repeating the claim that the militant group based in Lebanon routinely hides their arms in civilian populations.
Nonetheless, the Israeli government announced in prepared statement that they take full responsibility for their actions and will intiate an investigation into the Qana bombing. Ayalon told ABC News that Israel was taking this action "so we can do everything in the future not to repeat it."
Shattah did not blame Hezbollah.
"There is nothing that can excuse the Israeli killing of civilians," he said. "This is not justified, cannot be justified by anything."
The bombing prompted calls for a cease-fire from several corners of the world. Jordan's King Abdullah and Egyptian President Hosni Mubarak repeated calls for a cease-fire, while French President Jacques Chirac called the action "unjustified."
Pope Benedict XVI said in a statement released by the Vatican, "In the name of God, I call on all those responsible for this spiral of violence so that weapons are immediately laid down on all sides."
On "This Week", Burns said, "We're close, we think, to a political agreement between Israel and Lebanon."
Stephanopoulos, ABC News' chief Washington correspondent, pressed Burns on whether the worldwide chorus of criticism might pressure the United States to join the call for an immediate ceasefire.
"We want a ceasefire," Burns said. "We want to avoid a repetition of the situation where you essentially put a band aid over things. … We've got to have a view of a sustainable ceasefire."
Chatah repeatedly claimed, "It's not a question of refusing to meet [with Secretary Rice]," but acknowledged, "I can't really say [when the meeting will occur] but we will not stop working."
Burns said Secretary Rice will remain in Israel, but plans to continue diplomacy in Beirut are uncertain.
"She'll have to make a decision," Burns said. "We are acting very urgently to try and bring this conflict to an end."