The United States, responding to the latest outbreak of violence in the Middle East, called Sunday for restraint on all sides.
The appeal from the State Department (search) came as Arab leaders warned that a "circle of violence" could encompass the region after Israeli warplanes attacked deep inside Syria (search) for the first time in decades.
That attack followed a suicide bombing Saturday in Haifa, Israel for which the Palestinian Islamic Jihad took responsibility.
President Bush on Sunday telephoned condolences to Israeli Prime Minister Ariel Sharon (search), while Israeli Ambassador Daniel Ayalon conferred with White House and State Department officials.
"We urge all sides to exercise restraint and to keep in mind the consequences of their actions," the State Department said in a statement.
At the White House, an administration official said the United States repeatedly has told Syria that Washington believes it is on the wrong side in the fight against terrorism and that it must stop harboring terrorists.
Israel claimed its target was an Islamic Jihad (search) training camp. The Palestinian group denied it had a camp in Syria.
The State Department came down on Israel's side of that dispute. It said extremist groups, including Islamic Jihad, were present in Syria and it described Syria as a state sponsor of terror.
Sen. Joe Lieberman, D-Conn., compared Israel's bombing to U.S. strikes against al-Qaida bases in Afghanistan after the Sept. 11 attacks in New York and Washington.
Bush did not respond to a question about the Israeli attack as he left church Sunday morning.
Lieberman, a presidential candidate, called Israel "our most steadfast ally in the region ... an ally in a new way since September 11 — we're both victims of terrorism."
"No government can stand by and let that continue to happen," Lieberman told "Fox News Sunday."
"Unfortunately, the Syrians have continued to refuse American demands that they break up terrorist bases and headquarters in their country. And what the Israelis appear to have done in attacking Syria is not unlike what we did after September 11 in attacking training camps of al-Qaida in Afghanistan," Lieberman said.
Syrian President Bashar Assad, after meeting with Secretary of State Colin Powell in May in Damascus, indicated that his government had closed certain Palestinian offices.
But last month, Undersecretary of State John R. Bolton testified to Congress that Syria offers sanctuary and political protection to groups branded as terrorist by the United States.
Last weekend, national security adviser Condoleezza Rice said the United States is not "working as constructively with the Syrians as we need to. ... There is much more that Syria needs to do, and that message is being communicated to them."
The administration contends Syria is allowing militants to cross its border into Iraq to kill U.S. soldiers and is aggressively seeking to acquire and develop chemical, biological and nuclear weapons.
Lieberman said the Syrians "have to get on the right side of the war on terrorism or they're not going to be our allies and certainly not the Israeli allies."
Ending support for terrorism is the only way that the U.S.-backed plan for peace between Israel and the Palestinians can get back on track, Lieberman said.
"But that can't happen so long as terrorists operating from the Palestinian territories and being trained in places like Syria and Iran are killing civilians who are in a restaurant," Lieberman said.
Syria's Foreign Ministry said in a statement that it plans to lodge an "urgent complaint" against Israel with the United Nations.
Lieberman said that if Syria seeks "a broad-scale condemnation of the Israeli act, I hope very much the Bush administration will veto it."