A Palestinian stabbed and wounded an Israeli soldier in the neck in the southern West Bank on Wednesday and was shot dead by forces at the scene, the army and a hospital said.
A Palestinian teenager also succumbed to his wounds two weeks after being shot during clashes with Israeli forces.
The West Bank stabbing was the latest incident in nearly two months of knife, gun and car-ramming attacks by Palestinians and came a day after a visit by US Secretary of State John Kerry failed to produce any breakthrough.
"A Palestinian assailant stabbed and wounded an Israeli at the Al Fawwar junction," the military said in a statement. It later identified the victim as a soldier.
"In response to the immediate danger forces on site fired at the attacker."
A spokeswoman for Shaare Zedek hospital in Jerusalem said the stabber, who was taken there in critical condition, was pronounced dead after resuscitation efforts failed.
Palestinians identified him as Mohammad Shubaki, 19, from Al Fawwar refugee camp.
A doctor said he had suffered bullet wounds in his chest and stomach. The victim of the stabbing was in "stable" condition, a surgeon with Shaare Zedek's trauma unit told reporters.
Separately, a Palestinian shot by Israeli security forces two weeks earlier died of his wounds, the Palestinian health ministry said in a statement.
Ibrahim Abdul Haleem Dawood, 16, was shot in the heart during clashes with Israeli forces in Ramallah, the statement added, adding that several operations to try to save him had failed.
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On Tuesday, Kerry had hoped to mediate gestures that would ease tensions in separate talks with Prime Minister Benjamin Netanyahu and Palestinian president Mamud Abbas.
There were however scant signs of major progress, and Netanyahu told him that civilian Palestinian projects would be allowed to advance only when Israel experienced a "return of the quiet," an Israeli official said.
The premier also conditioned Palestinian construction in Israeli-controlled parts of the West Bank on international recognition of Israel's right to build in existing settlement blocs.
The United States rejected the notion of settlement recognition with "a big no," a State Department spokesman said.
Jewish settlements in the occupied West Bank are seen as illegal under international law and major stumbling blocks to peace efforts since they are built on land Palestinians see as part of their future state.
"Every US administration since 1967, Democrat and Republican alike, has opposed Israeli settlement activity beyond the 1967 lines, and this administration's been no different and will be no different," State Department deputy spokesman Mark Toner said.
Kerry at the same time expressed strong support for Israel and condemned Palestinian attacks when he met Netanyahu.
In brief remarks after meeting Abbas in Ramallah, Kerry also expressed sympathy for the Palestinians' "very dire" situation and concerns "about the violence," while stressing US commitment to a Palestinian state.
Violence since October 1 has left 94 Palestinians dead, including one Arab Israeli, as well as 17 Israelis -- including two Israeli-Americans -- one American and an Eritrean.
Many of the Palestinians killed have been alleged attackers, while others were shot during demonstrations and clashes with Israeli security forces.