By Maayan Lubell and Nidal al-Mughrabi
JERUSALEM/GAZA (Reuters) - Israeli security forces on Saturday shot dead two Palestinians aged 12 and 15 in protests along Gaza's border fence, Palestinian medics said, and Israeli police said they killed three Palestinian assailants in separate violence in Jerusalem.
Eleven days of bloodshed in which four Israelis and 19 Palestinians have been killed in Jerusalem, the Israeli-occupied West Bank, Gaza and in Israeli cities have raised concerns about a new Palestinian uprising.
On Saturday two Palestinians were shot dead by police after stabbing at least four Israelis in separate knife attacks near Jerusalem's walled Old City, Israeli police spokesman Micky Rosenfeld said.
He said paramilitary police also killed a Palestinian militant after coming under fire from him during late-night clashes at the Shuafat refugee camp in East Jerusalem.
Hamas, the Islamist Palestinian militant group which controls the Gaza Strip, said in a statement that the Shuafat shooter was one of its members. "The hero martyr fought the Israeli occupation with language they understand," Hamas said.
In Gaza, Israeli soldiers shot dead the Palestinian boy and teenager as they were taking part in protests near the Israeli border security fence, Palestinian medical officials said.
An army spokeswoman said the protesters, in an Israeli-declared no-go security zone by the border, were hurling burning tyres and stones towards the soldiers, who fired warning shots in the air before shooting "at the main instigators".
Near the Old City's Damascus Gate a Palestinian stabbed two police officers, seriously wounding one of them, a few hours after a 16-year-old Palestinian stabbed and wounded two ultra-Orthodox Jewish men nearby, Rosenfeld said.
The violence has been fuelled by Palestinian fears that visits by Jewish groups and lawmakers to the Jerusalem Old City plaza revered in Judaism as the site of two destroyed biblical temples, are eroding Muslim religious control of the al-Aqsa mosque compound, Islam's third holiest shrine.
Israeli Prime Minister Benjamin Netanyahu has said repeatedly that he will not allow any change to the arrangements under which Jews are allowed to visit the site but non-Muslim prayer is banned.
His assurances over conditions at the site, known as Temple Mount to Jews and Noble Sanctuary to Muslims, have done little to quell alarm among Muslims across the region.
The almost daily Palestinian knife attacks and clashes between Israeli soldiers and stone-throwing Palestinians are not at the levels of violence of past Palestinian uprisings, but the escalation has prompted talk of a third "intifada".
Ali al-Qaradaghi, a prominent Muslim cleric, urged worshippers on Saturday to join what he described as an uprising.
"Every Muslim should contribute to the Intifada that started for the sake of al-Aqsa and Palestine," he wrote on his Twitter account. Al-Qaradaghi is a cleric at the Doha-based International Union of Muslim Scholars, headed by the spiritual leader of the Muslim Brotherhood, Sheikh Youssef al-Qaradawi.
In 2000, Ariel Sharon, then Israel's opposition leader and later prime minister, visited the al-Aqsa compound. That enraged Palestinians and led to an uprising that continued for five years and left about 3,000 Palestinians and 1,000 Israelis dead.
Clashes between Palestinians and Israeli troops also broke out on Saturday near the West Bank cities of Hebron and Ramallah and again at the Shuafat camp. Scores of Palestinians were injured including 17 hit by live gunfire, according to the Palestinian Red Crescent.
Protests have also spread to several Arab towns in Israel.
Both Netanyahu and Palestinian President Mahmoud Abbas have called for calm and Palestinian police continue to coordinate with Israeli security forces to try to restore order, but there are few signs of the violence dying down.
Palestinians want East Jerusalem, the West Bank and Gaza - lands Israel captured in the 1967 Middle East war, for a future state. U.S.-brokered peace talks broke down in April 2014.
(Additional reporting by Noah Browning in Dubai; Ali Sawafta in Ramallah and Nidal al-Mughrabi in Gaza; Writing by Maayan Lubell; Editing by Mark Heinrich)