The United States on Friday condemned "in the strongest possible terms" Thursday's attack on a Palestinian taxi in the West Bank, which left six people lightly to moderately wounded, including two children.

"We extend our deepest sympathies to the victims, among them children, and we hope for their speedy recovery. We note that the Government of Israel has also condemned this heinous attack and pledged to bring the perpetrators to justice," the US State Department said in a statement.

"We look to Israeli law enforcement officials to do so expeditiously. We urge all parties to avoid any actions that could lead to an escalation of violence," the statement continued.

Earlier Friday, Prime Minister Binyamin Netanyahu and Police Inspector General Yochanan Danino vowed to bring to justice the unknown assailants who threw a Molotov cocktail at the taxi outside the Gush Etzion settlement of Bat Ayin on Thursday night.

Results from an initial investigation raised fears that Jewish extremists could have perpetrated the attack.

Netanyahu sent a message to Palestinian Authority President Mahmoud Abbas and PA Prime Minister Salam Fayyad on Friday, saying that he viewed the firebomb attack as a "very serious" offense and that all efforts would be made to bring the perpetrators to justice.

Netanyahu's special envoy Yitzhak Molcho called PA chief negotiator Saeb Erekat with the message for Abbas and Fayyad.

The prime minister added that he would ensure the Palestinian victims of the attack were receiving proper medical treatment.

During a briefing held at the Temple Mount complex on the occasion of the last Friday of Ramadan, Danino referred to the Molotov cocktail attack as "a very severe incident" and said he has instructed police to do whatever it takes to bring the perpetrators to justice as soon as possible.

Danino added that Israel Police "won't allow extremist criminals to disrupt and inflame daily life across Israel, in particular in areas that are especially sensitive."

Judea and Samaria Commander Brigadier General Hagai Mordechai said Thursday that the incident could compromise security and stability in the West Bank.

On Thursday night Mordechai increased IDF presence along friction points on West Bank roads.

A security source said that it would have been obvious to the assailants that they were targeting a Palestinian taxi, because the attack occurred in day light in a place with good visibility.

The yellow vehicle with a green Palestinian license plate, typically of West Bank Palestinian taxis, could not have been mistaken for any other kind of vehicle, the security source said.

But, the source added, that the investigation was still in its initial stages.

According to the police, the taxi flipped and burst into flames after the Molotov cocktail hit it. Paramedics evacuated all six wounded to Hadassah Ein Kerem Hospital shortly thereafter.

Police said they found a second, ready-to-use Molotov cocktail near the site of the firebombing. They would not comment as to whether or not Jewish extremists firebombed the taxi, saying they are still in the initial stages of the investigation.

The Shin Bet joined police and IDF troops in the search for the assailants, which is currently ongoing in the West Bank.

The Shin Bet had initially refused to comment on whether or not they consider the incident a “Price Tag” attack, the name given to attacks by Jewish extremists against Palestinians in order to protest government policies, saying that the investigation is still in its initial phase. The Shin Bet also placed a gag order on details of the attack.

The Tag Meir group condemned the attack in a statement released by the organization's chairman Dr. Gadi Gvaryahu, saying "We must not allow such Price Tag attacks to become commonplace." Gvaryahu added: "The security apparatus must do everything in its power to arrest those responsible for attacking an innocent Palestinian family."

Tovah Lazaroff contributed to this report.

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