A top US State Department official cautioned Israel Thursday on the use of force in Gaza as the IDF mulls an invasion to stop the rocket fire from the coastal strip. "We urge caution and proportionality," David Welch, assistant secretary of state for Near Eastern affairs, told regional media at a press briefing here. "Israel has the right to defend itself, just as any sovereign nation does," but "how it exercises that right is important to Israel and the United States and to everyone else," he said. "Unchecked large-scale violence in Gaza could easily overwhelm the [Annapolis] process, and that means months of American diplomacy goes down the drain," said US Institute of Peace research associate Scott Lasensky, who recently coauthored the book Negotiating Arab-Israel Peace. So the US, in its efforts to continue the peace process, wants to keep the situation in Gaza "at some sort of manageable level," Lasensky said. The approach, he said, was consistent with American policy that has long supported the ability of Israel to take targeted military steps to defend itself, but has opposed attacks that serve to send a message rather than achieve an objective. Welch also argued that Palestinians in Gaza should stop the rocket fire out of their own self-interest. "If people in Gaza are to enjoy a better life, then it is incumbent upon those who claim they control the situation in Gaza to stop these actions which actually bring no benefit and only harm," he said. During the briefing, Welch also brushed aside criticism leveled by Palestinian Authority Prime Minister Salaam Fayad last week in Washington at the slow progress on the ground in the shadow of negotiations with Israel. "I respect the judgment of Prime Minister Fayad of what he would like to see from any negotiating process. On the Israeli side, there will be similar judgments about what they would like to see," Welch said. He added, "Everybody's impatient to work on this problem and would like to see progress, so I don't expect that if you asked them the question on any day that they're going to say that they're very happy with the result, especially when this is just starting."