The United States joined Israel in condemning the International Criminal Court decision to open a preliminary probe into possible war crimes committed against Palestinians, blasting it as a "tragic irony".
ICC prosecutor Fatou Bensouda said her office would conduct an "analysis in full independence and impartiality" into alleged war crimes by Israel, including those committed during last year's Gaza offensive.
Her decision comes after Palestine formally joined the ICC earlier this month, allowing it to lodge war crimes and crimes against humanity complaints against Israel as of April.
Nearly 2,200 Palestinians and 73 Israelis were killed during last summer's war in Gaza.
The US criticized the decision late Friday, saying it opposed actions against Israel at the ICC as "counterproductive to the cause of peace".
"It is a tragic irony that Israel, which has withstood thousands of terrorist rockets fired at its civilians and its neighborhoods, is now being scrutinized by the ICC," US State Department spokesman Jeff Rathke said in a statement.
Israeli Prime Minister Benjamin Netanyahu had earlier reacted angrily to the prosecutor's decision, calling it "scandalous" and "absurd" since "the Palestinian Authority cooperates with Hamas, a terror group that commits war crimes, in contrast to Israel that fights terror while maintaining international law, and has an independent justice system."
Gambian-born Bensouda had earlier stressed that "a preliminary examination is not an investigation but a process of examining the information available... on whether there is a reasonable basis to proceed with an investigation."
Buildings destroyed in the 50-day Gaza war between Israel and Hamas-led militants are seen during a winter storm in Gaza City's Al-Shejaiya suburb on January 6, 2015.
Bensouda will decide at a later stage whether to launch a full investigation.
Stalled US-led peace process
Israel began a massive crackdown on the West Bank on June 13 after the kidnapping and subsequent murder of three Israeli teenagers, triggering a series of events that led to the seven-week Gaza war.
Palestine's move to join the ICC is also seen as part of a shift in strategy to internationalize its campaign for statehood and move away from the stalled US-led peace process.
The Palestinians were upgraded from observer status to UN "observer state" in 2012, opening the doors for them to join the ICC and a host of other international organizations.
Israel reacted swiftly on Friday, slamming the announcement.
Israeli Foreign Minister Avigdor Lieberman said the sole purpose of the preliminary examination was to "try to harm Israel's right to defend itself from terror" and he said the decision was "solely motivated by political anti-Israel considerations."
Lieberman accused the court of double standards for not examining the mass killings in Syria or other conflict zones, investigating instead "the most moral army in the world".
Israel earlier this month delayed transferring some $127 million in taxes it collects on behalf of the Palestinians in retaliation for the attempts to press war crimes charges against the Jewish state.
Palestinian foreign minister Riyad al-Malki welcomed the ICC's move.
"Everything is going according to plan, no state and nobody can now stop this action we requested," he told AFP.
"In the end, a full investigation will follow the preliminary one."
'Justice for victims'
Rights group Amnesty International welcomed the ICC's announcement saying it "could pave the way for thousands of victims of crimes under international law to gain access to justice."
But the initial probe could lead to an investigation into crimes "committed by all sides", Amnesty stressed in a statement.
Friday's announcement is the second such initial probe by the ICC's prosecutor into the situation in Palestine.
The Palestinian Authority in 2009 lodged a complaint against Israel but the ICC prosecutor said in 2012 after "carefully considering legal arguments" it could not investigate because of the Palestinians' status at the UN.
At the time the Palestinians' "observer" status blocked them from signing up to the ICC's founding Rome Statute.
The ICC, which sits in The Hague in the Netherlands, is the world's first independent court set up in 2002 to investigate genocide, war crimes and crimes against humanity.
But it can only probe alleged crimes in countries that have ratified the Rome Statute, or accepts the Hague-based court's jurisdiction for a certain time period, or through a referral by the UN Security Council.
Currently, chief prosecutor Bensouda is also running preliminary investigations in Afghanistan, Colombia, Georgia, Guinea, Honduras, Iraq and Ukraine.
While 123 countries have now ratified the Rome Statute, Israel and the United States have not.