Secretary of State John Kerry
Secretary of State John KerryReuters

Hours after his spokesman condemned the latest round of terrorist attacks on Israeli civilians, Secretary of State John Kerry on Tuesday evening reiterated the condemnation and urged calm.

"The United States condemns in the strongest terms possible the terrorist attacks against Israeli civilians," Kerry told reporters, according to the AFP news agency.

"Naturally, we mourn the loss of any life, no matter who it is, but this violence and any incitement to violence has got to stop," he warned.

"We continue to stress the importance of all -- all -- persons of responsibility to condemn the violence on either side, and to avoid provocative statements," Kerry continued.

"I continue to urge all sides to take affirmative steps to restore calm and I will stay in very close touch with leaders in the region in the days ahead," he said.

Earlier Tuesday, State Department spokesman John Kirby condemned "in the strongest terms" the latest terrorist attacks and added, "We remain deeply concerned about escalating tensions and urge all sides to take affirmative steps to restore calm and prevent actions that would further escalate tensions."

Two Israelis were killed on Tuesday when two terrorists attacked passengers with knives and a gun on a bus in Jerusalem's Armon Hanatziv neighborhood. 

In a separate attack, also in Jerusalem, another Israeli was killed when an Arab terrorist and Bezeq employee drove his company car into a crowd of Jews at a bus stop then jumped out with a knife.

Five other Israelis were also wounded in two stabbing attacks in Ra'anana, a city in the Sharon region north of Tel Aviv. 

Tuesday's four attacks were only the latest in a two-week wave of violent Arab terror across the Jewish state. 

After the attacks, Prime Minister Binyamin Netanyahu vowed to use "all means" at his disposal to restore order.