The United States on Wednesday condemned the killing of a Palestinian youth in what is being investigated as possible revenge for the murders of three Israeli teenagers, warning acts of vengeance would worsen an explosive situation.

An Israeli official castigated Kerry for the strongly worded statement, which came hours after the death of 16-year-old Muhammad Abu Khdeir, since it was issued before police had declared a motive for the crime.

“There are no words to convey adequately our condolences to the Palestinian people,” Secretary of State John Kerry said in the statement.

US President Barack Obama’s national security adviser Susan Rice said on Twitter that the murder of Abu Khdeir was “heinous” and called on both Israelis and Palestinians to avoid a cycle of retribution and revenge.

According to the testimony of local residents, Abu Khdeir was seen being forced into a car by three Israelis in East Jerusalem. Police later confirmed a body was found in a forest in West Jerusalem.

16-year-old Muhammed Abu Khdeir, a Palestinian teenager whose body was found Wednesday, July 2 in Jerusalem's forest area. The Palestinian teenager was reportedly kidnapped and killed by Jewish extremists in an apparent act of revenge for the killing by terrorists of three Israeli youths (Photo credit: AFP via family handout)

16-year-old Muhammed Abu Khdeir, a Palestinian teenager whose body was found Wednesday, July 2 in Jerusalem’s forest area. The Palestinian teenager was reportedly kidnapped and killed by Jewish extremists in an apparent act of revenge for the killing by terrorists of three Israeli youths (Photo credit: AFP via family handout)

DNA tests proved the body was that of the missing teenager, his family said.

The attack is believed by some to have been carried out in revenge for the kidnap and killing June 12 of three Israeli teenagers, whose bodies were found on Monday, by Palestinian terrorists. Police are investigating other motives as well.

In his statement, Kerry condemned the killing in “the strongest possible terms.”

He said it was sickening to think a young boy could be “snatched off the streets and his life stolen from him and his family.”

Kerry noted that Prime Minister Benjamin Netanyahu had condemned the killing and urged Israelis not to take the law into their own hands.

“Those who undertake acts of vengeance only destabilize an already explosive and emotional situation,” Kerry said.

“We look to both the government of Israel and the Palestinian Authority to take all necessary steps to prevent acts of violence and bring their perpetrators to justice.

“At this tense and dangerous moment, all parties must do everything in their power to protect the innocent and act with reasonableness and restraint, not recrimination and retribution.”

An Israeli official told The Times of Israel that Kerry’s remarks seemed premature, considering the wait-and-see approach the US government had initially displayed last month regarding the abduction and killing of the three Israeli teens.

“How does he [Kerry] know it is an act of vengeance? If it is, obviously the strong condemnation is more than justified. But, apparently, waiting for information, waiting for evidence from intelligence or police investigation, is only required when the victim is Israeli,” said the official.

White House press secretary Josh Earnest also said the United States “condemns in the strongest possible terms” the death of Abu Khdeir.

“We hope to swiftly see the guilty parties brought to justice,” Earnest told reporters. “We call on the government of Israel and the Palestinian Authority to take all necessary steps to prevent an atmosphere of revenge and retribution. People who undertake acts of vengeance will only destabilize an already volatile and emotional situation.”

Earnest declined to say whether the US considers the teen’s death an act of revenge for the three Israeli teens, but said the US doesn’t want to see the situation spiral out of control and lead to further violence.

Netanyahu ordered a swift probe into the killing Wednesday. Police spokesman Micky Rosenfeld told The Times of Israel that officials were investigating the possibilities that Abu Khdeir was killed in a family honor killing or that it was a nationalistically motivated slaying.

The killing set off violent riots in the East Jerusalem neighborhood of Shuafat, where protesters clashed with police and burned down a light rail stop.

British Prime Minister David Cameron on Wednesday condemned the killing as “appalling.” He also urged Israel and the Palestinians to exercise restraint as tensions rise.

Tensions have soared since June 12 when the three Israeli teenagers disappeared while hitchhiking in the West Bank. Their bodies were found on Monday afternoon near Hebron, with Israel blaming Hamas and vowing to hit it hard.

Lazar Berman and Raphael Ahren contributed to this report.