Jerusalem (AFP) - Two Palestinians opened fire on a bus and near Jerusalem's Old City on Wednesday, seriously wounding one person, as an upsurge in attacks marred a visit by US Vice President Joe Biden.
Six separate attacks have taken place shortly before or after Biden's arrival on Tuesday, including a stabbing spree on the Tel Aviv waterfront by a Palestinian that killed an American tourist and wounded 12 people.
The Tel Aviv stabbings in the Jaffa port area took place as Biden met former Israeli president Shimon Peres about a kilometre away on Tuesday.
The vice president "condemned in the strongest possible terms the brutal attack which occurred in Jaffa during his meeting with president Peres," his office said, adding "there is no justification for such acts of terror".
The US State Department identified the dead American as Taylor Allen Force, a 29-year-old Texas native and army veteran.
Biden was to meet Israeli Prime Minister Benjamin Netanyahu in Jerusalem on Wednesday and Palestinian president Mahmud Abbas in Ramallah later.
A police spokesman said there was "heightened security across Jerusalem".
- String of attacks -
The White House has said Biden will not be pursuing any major new peace initiatives during his visit despite a wave of violence that erupted in October.
The number of attacks had somewhat diminished recently and Israeli security forces were probing whether the flare-up was connected to Biden's visit.
Violence in Israel and the Palestinian territories since last October has killed 188 Palestinians and 28 Israelis.
Most of the Palestinians were killed while carrying out knife, gun or car-ramming attacks, Israeli authorities say.
Others were shot dead by Israeli forces during clashes or demonstrations.
On Wednesday the two Palestinians, both around 20-years-old, first 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, seriously wounding a 50-year-old man. Medics said the victim may have been a Palestinian from east Jerusalem.
The two assailants were then shot and killed by police.
In a separate incident later in the morning, a Palestinian tried to stab Israeli forces at a checkpoint in the occupied West Bank and was shot dead, the army said.
Three other assaults occurred on Tuesday in addition to the stabbings that killed the American, including two in Jerusalem and one in Petah Tikva near Tel Aviv.
One saw a Palestinian shoot and seriously wound two Israeli police officers in Jerusalem before being shot dead.
In another, a Palestinian woman attempted to stab Israeli police forces in Jerusalem's Old City before being shot dead.
In Petah Tikva, a Palestinian stabbed an ultra-Orthodox Jew in a liquor store. The victim and owner of the shop pounced on the attacker, seized his weapon and killed him, police said.
- Talks overshadowed -
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 visit comes with Obama having acknowledged there will be no comprehensive agreement between Israelis and Palestinians before he leaves office in January 2017.
Biden's talks are expected to include discussions 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.
Biden and Netanyahu also plan to discuss the fight against the Islamic State jihadist group.
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.
After his visit to Israel and the Palestinian territories, Biden will travel to Jordan. He visited the United Arab Emirates before arriving in Tel Aviv on Tuesday.