Israeli officials say suspected Arab militants carried out two separate attacks Friday, killing three people and wounding six others.
Authorities said an Italian tourist was killed and five others were wounded in a car ramming attack in Tel Aviv.
In an earlier Friday attack, two Israeli sisters were killed, and their mother was wounded in a shooting in the occupied West Bank.
The Palestinian militant group Hamas, which rules Gaza, praised the shooting attack but stopped short of claiming responsibility.
The U.S. State Department strongly condemned Friday's "terrorist attacks in the West Bank and Tel Aviv."
In a statement, it said the attacks affected citizens of Israel, Italy and Britain and that the “targeting of innocent civilians of any nationality is unconscionable."
Prime Minister Benjamin Netanyahu said he was calling up all reserve forces in Israel's border police and directing the national military to mobilize additional forces "to confront the terror attacks," his office said.
Also Friday, Israeli airstrikes hit Lebanon and the Gaza Strip in retaliation for rocket attacks that Israel blames on the Islamist group Hamas. The violence has sparked fears of a broader conflict.
While tensions simmered Friday, Ramadan prayers at the Al-Aqsa Mosque in Jerusalem, where violence between Israeli police and Muslim worshippers erupted earlier in the week, were conducted without major incident Friday. Apart from some stone-throwing, police said the compound was quiet.
"Nobody wants an escalation right now," an Israeli army spokesman said. "Quiet will be answered with quiet, at this stage I think, at least in the coming hours."
One official with a Palestinian militant group told Reuters they were ready to keep the calm should Israel do the same, with the group having "made its point."
Tensions have been brewing in the region following a clash Wednesday between Israeli police and Palestinians inside Jerusalem's Al-Aqsa Mosque, Islam's third-holiest site. The site is part of the Old City of Jerusalem, sacred to Christians, Jews and Muslims. The al-Aqsa compound overlooks the Western Wall, a sacred place of prayer for Jews for whom the Temple Mount is their most sacred site. Jews believe biblical King Solomon built the first temple there 3,000 years ago.
During Wednesday's clashes, Israeli police raided al-Aqsa and beat Palestinian worshippers, arresting and removing hundreds of people from the compound in what they said was an effort to remove agitators holed up in the mosque.
Video of the raid drew condemnation from across the Arab world.
During Ramadan, Muslims see it as a religious duty to remain overnight and pray at mosques.
On Thursday, Israel said dozens of rocket attacks were launched into Israel from Lebanese territory. Israel blamed Hamas for the attacks, although the group did not say it was behind them.
The salvoes included the largest from Lebanon since a 2006 war with Iran-backed Hezbollah. They interrupted the Jewish holiday of Passover and sent residents running for shelters.
Israel called on the United Nations Security Council to condemn Lebanon and Hamas for the attack.
The United States, Britain and the United Nations, while recognizing Israel's right to self-defense, have urged restraint.
Some information for this report came from The Associated Press, Agence France-Presse and Reuters.
