Jerusalem: US Vice President Joe Biden on Wednesday implicitly criticised Palestinian leaders for not condemning attacks against Israelis, as an upsurge in violence marred his visit.
Six separate attacks took place shortly before or after Biden's arrival Tuesday, including a stabbing spree on Tel Aviv's waterfront by a Palestinian who killed an American tourist and wounded 12 people.
The stabbings in the Jaffa port area took place as Biden met former Israeli president Shimon Peres about a kilometre away on Tuesday.
Biden said his wife and grandchildren had been having dinner on the beach not far from the site of the stabbings.
"The United States of America condemns these acts and condemns the failure to condemn these acts," Biden said while meeting Israeli Prime Minister Benjamin Netanyahu.
"The kind of violence we saw yesterday, the failure to condemn it, the rhetoric that incites that violence, the retribution that it generates, has to stop."
Biden offered his condolences to the family of the American victim, 29-year-old Taylor Force, whom he noted served in the military in Afghanistan and Iraq.
Palestinian president Mahmud Abbas has repeatedly called for peaceful resistance against the Israeli occupation, but has not specifically condemned a wave of knife, gun and car-ramming attacks that erupted in October.
Islamist movement Hamas, which runs the Gaza Strip, often praises such attacks.
Biden will travel to Ramallah later Wednesday to meet Abbas.
A large number of the attackers have been young people, including teenagers, who appear to have been acting on their own.
Many analysts say Palestinian frustration with Israeli occupation and settlement building in the West Bank, the complete lack of progress in peace efforts and their own fractured leadership have fed the unrest.
Israel blames incitement by Palestinian leaders and media as a main cause of the violence, which has killed 188 Palestinians and 28 Israelis since October.
Most of the Palestinians were killed while carrying out attacks, Israeli authorities say.
Others were shot dead by Israeli forces during clashes or demonstrations.
- String of attacks -
The White House has said Biden will not be pursuing any major new peace initiatives during his visit despite the wave of violence.
The number of attacks had somewhat diminished recently and Israeli security forces were probing whether the flare-up was connected to Biden's visit.
On Wednesday two Palestinians, 19 and 21, shot at a bus from their car in an ultra-Orthodox Jewish neighbourhood of northern Jerusalem, police said.
A driver returned fire at the assailants before they fled.
Later they opened fire again just outside Jerusalem's Old City.
A 50-year-old man, thought to be a Palestinian from east Jerusalem, was seriously wounded.
Israeli authorities first attributed his injury to the assailants, but said later they were investigating whether it was the result of police gunfire.
The two assailants were shot and killed by police.
In a separate incident later in the morning, a 16-year-old Palestinian tried to stab Israeli forces at a checkpoint in the occupied West Bank and was shot dead, the army said.
Three other attacks occurred on Tuesday in addition to the stabbings that killed the American, including two in Jerusalem and one in Petah Tikva near Tel Aviv.
Biden's visit had already been overshadowed by a new blow to the rocky relationship between US President Barack Obama and Netanyahu.
Netanyahu's decision not to accept an invitation for talks with Obama in Washington later this month "surprised" the White House, which first learned of it through news reports.
The issue did not come up in public comments by Biden and Netanyahu.
Both countries have been seeking to set aside their deep disagreement on the Iran nuclear deal, which Netanyahu strongly opposed, and show that the ties between the two traditional allies remain strong.
They have been working on a new 10-year defence aid package for Israel, currently worth some $3.1 billion annually in addition to spending on projects such as missile defence.
"The United States stands firmly behind Israel's right to defend itself, as we are defending ourselves," Biden said.
"That is why we have done more to bolster Israel's security than any other administration in history ... It doesn't mean we don't disagree, but you never need to doubt that the United States of America has Israel's back."
Senior Palestinian official Ahmed Majdalani said he was expecting "nothing" from Biden's visit.
"Mr. Biden is only coming to the region in the context of his plans regarding the fight against terrorism in Syria, not for us," he told AFP, referring to talks between Biden and Netanyahu on the Islamic State group.