Paris Slams 'Cowardly Murder' of 3 Israelis, UK Says 'Inexcusable Terror Act'

French President Francois Hollande on Monday condemned what he described as the "cowardly murder" of three Israeli teenagers whose bodies were found in the West Bank three weeks after they went missing.

Hollande "strongly condemns the cowardly murder of Eyal Ifrach, Naftali Frankel and Gilad Shaer and offers his sincere condolences to their families as well as to the Israeli authorities," the presidency said in a statement.

Voicing concern at the surge of violence in the Palestinian territories, Hollande condemned the firing of rockets from Gaza into Israel and called for "everything to be done to avoid new victims and the risk of an escalation of violence."

The surge in rocket fire coincided with the start of a huge Israeli arrest operation in the West Bank aimed at finding the teens, whose bodies were discovered in a field near Halhul.

It was not immediately clear how the youths died but Israel's deputy defense minister Danny Danon said they were murdered by "Hamas terrorists" as he called for an operation to "eradicate" the Islamist movement.

Meanwhile, British Prime Minister David Cameron said the killing of the three Israelis is an "inexcusable act of terror" and Britain will back Israel as it seeks justice.

"I am deeply saddened by the news that the bodies of the three Israeli boys kidnapped on 12 June have been found this evening," Cameron said in a statement.

"This was an appalling and inexcusable act of terror perpetrated against young teenagers. Britain will stand with Israel as it seeks to bring to justice those responsible."

"Tonight my thoughts and prayers are with the families of Gilad, Naftali and Eyal. No parent should have ever to suffer such heartache or grief."

Israel has repeatedly accused Hamas of kidnapping the teens, two of whom were minors, and launched a major crackdown on the movement's West Bank infrastructure.

Hamas has dismissed the Israeli allegations as "stupid" with its spokesman Sami Abu Zuhri accusing Israel of fabricating the kidnapping as an excuse to crack down on the Islamist movement.

"The disappearance and murder of the three Israelis is only based on the Israeli narrative, and the occupation is trying to use this story to justify its extensive war against our people, against resistance and against Hamas," he said.