The killing of 17-year-old Mohammed Abu Khdair on Wednesday was condemned by both Israeli and Palestinian leaders.The murder sparked fierce clashes amid claims it was in revenge for the killing of three Israeli youths.Meanwhile Palestinian militants in Gaza fired several rockets at Israel. Israel responded with a series of air strikes on the territory early on Thursday.Israeli officials said 20 mortars and rockets were fired."The Israeli Air Force attacked 15 terror sites in Gaza early Thursday morning," an Israel Defence Forces official said."The targets included weapons manufacturing sites as well as training facilities," the official added.Ashraf Al Qidra, from Gaza's Ministry of Health, told the BBC that 10 Palestinians were injured in the air strike and taken to hospital.'Strongest punishment'Mohammed Abu Khdair's funeral will be held on Thursday following noon prayers at around 13:00 local time (10:00 GMT).Correspondents say there are fears the funeral will be followed by more clashes like those which erupted outside the teenager's home on Wednesday.Protesters threw stones at officers, who responded by firing sound bombs, tear gas and rubber bullets.The boy was seen being forced into a car in Shufat, East Jerusalem, early on Wednesday.His body was later found, bearing the marks of violence, in West Jerusalem.On Wednesday, Palestinian President Mahmoud Abbas accused Jewish settlers of killing the 17-year-old, calling for the "strongest punishment against the murderers".Agence France-Presse news agency quoted the Palestinian militant group Hamas as telling Israeli leaders: "Our people will not let this crime pass... You will pay the price for these crimes."Israeli Prime Minister Benjamin Netanyahu said the murder was "despicable" and that he had ordered police to work "as quickly as possible to find out who was behind the heinous murder of the youth".He called on both sides "not to take the law into their own hands".The family of one of the three murdered Israeli teenagers also issued a statement condemning the latest killing."If the Arab youth was murdered because of nationalistic motives then this is a horrible and horrendous act," the statement from the family of Naftali Frenkel said.Israeli police have urged caution over the motives for the killing, saying they are still investigating.The killing came a day after funerals were held in the West Bank for the three Jewish seminary students whose bodies were found near the city of Hebron on Monday, two-and-a-half weeks after they were abducted.Map of Jerusalem showing locations of kidnapping and body(BBC)Bakudaily.az