They were the latest in a wave of Palestinian knife gun and car-ramming attacks that erupted in October andcame as US Ambassador to the United Nations Samantha Power visited Israel and the Palestinian territories for talks with leaders from both sides.

In the first incident two 15-year-olds attacked an Israeli patrol west of the city of Jenin with rocks before firing on soldiers with a rifle an army statement said.

"The force responded to the shooting and fired towards the attackers resulting in their deaths" it said.

The Palestinian health ministry named those killed as Nihad Waked and Fuad Waked. They were not thought to be closely related.

Later in the day a Palestinian tried to stab Israeli border police between Jerusalem and Bethlehem in the West Bank before being shot dead Israeli authorities said.

The Palestinian health ministry identified the assailant as Naim Safi 17 who was from a village near Bethlehem.

Also on Sunday a young Palestinian woman tried to stab an Israeli policeman but was shot in the attempt in the flashpoint West Bank city of Hebron Israeli police said.

She was taken to hospital in critical condition.

Police said the attacker drew a knife on a border police officer at a checkpoint and the officer who was unharmed shot her. She was identified as Yasmin al-Zaru 20.

The incident took place close to the shared religious site known to Jews as the Cave of the Patriarchs and to Muslims as the Ibrahimi Mosque.

Tensions are high at the site -- a 17-year-old Palestinian was shot dead in a stabbing attempt there on Saturday.

- Shootout in Jerusalem -

Late Sunday violence also flared in central Jerusalem when two armed Palestinians attacked Israeli police just outside the Old City walls before being shot dead by officers police told AFP.

A police statement later said that one was spotted carrying a bag in a way that made officers suspicious and when they ordered him to drop it he pulled out a weapon and took aim but was shot dead before he could pull the trigger.

A second gunman then opened fire but was killed by police without wounding any officers it said

The statement said the attackers both about 20 years old were armed with"improvised automatic weapons".

Since the current round of bloodshed erupted at the beginning of October 172 Palestinians have been killed by Israeli forces.

Most were carrying out attacks but others died during clashes and demonstrations.

The violence has claimed the lives of 26 Israelis as well as an American a Sudanese and an Eritrean according to an AFP count.

Many of the assailants have been teenagers who appear to have acted on their own.

Some 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.

Questions have been raised over whether Israeli forces have used excessive force in certain cases allegations they firmly reject.

International efforts to halt the violence have so far failed.

US ambassador Power said she intended to discuss her country's "commitment to two states side-by-side in security and peace" during her visit.