Israeli Prime Minister Benjamin Netanyahu praised Palestinian president Mahmud Abbas Tuesday for condemning the alleged kidnapping of three teenagers by Hamas, but slammed his unity pact with the Islamist movement.

Netanyahu's comments came as Israel began to wind down a massive crackdown on Hamas, having arrested hundreds of its members in an operation to find the youngsters who went missing in the southern West Bank nearly two weeks ago.

"I appreciate what president Abbas said a few days ago in Saudi Arabia, rejecting the kidnapping," Netanyahu told his Romanian counterpart Victor Ponta at a meeting in Jerusalem.

"I think these were important words," he said.

Abbas has condemned the alleged kidnapping, and last week told a meeting of the Organisation of Islamic Cooperation in Saudi Arabia that "those who kidnapped the three teenagers want to destroy us".

"We will hold them accountable," he said, but stopped short of blaming Hamas.

Israel immediately accused its Islamist foe of kidnapping the youngsters, who went missing on June 12 at a hitchhiking spot near the city of Hebron.

The Jewish state has used the abduction as a pretext to uproot the Islamist movement's West Bank network, arresting a total of 354 Palestinians, 269 of them Hamas members, according to the army.

Hamas has not claimed the abduction, and Israel has provided no evidence for its involvement.

Abbas has pledged to continue security coordination with Israel, which he said was in Palestinians' "best interest" since it would "help protect us".

Israel seized on the opportunity presented by the operation to try to rupture a reconciliation agreement between Abbas and Hamas, which saw the two sides form a merged administration for the West Bank and Gaza earlier this month for the first time in seven years.

In remarks aired Tuesday, Hamas chief Khaled Meshaal told Al-Jazeera television that "we do not have information about what happened," but stressed his support for "every resistance attack against the Israeli occupation".

- 'No alliance with kidnappers' -

Netanyahu slammed Meshaal's remarks, reiterating that if "Abbas really means what he said about the kidnapping, and if he is truly committed to peace and to fighting terrorism, then logic and common sense mandate that he break his pact with Hamas."

"There can be no alliance with the kidnappers of children," he said.

Defence Minister Moshe Yaalon said Israel was beginning to wind down its arrest operation, which has cost the lives of four Palestinians and sparked public anger in the West Bank.

"The operation by the Israeli army against Hamas has been mostly completed," he told public radio, adding that the number of wanted Palestinians still at large had greatly diminished as "dozens and dozens" were now in custody.

Tensions have risen among Palestinians over the death toll from the Israeli operation, particularly as it comes in the run-up to the start next week of the Muslim holy month of Ramadan.

A former top army commander, Israel Ziv, said it was in Israel's interest to focus the operation on intelligence gathering rather than physical intimidation.

"There are casualties, and definitely we have to reconsider when is the right timing to change this mode of operation and to move towards what is more effective, which is... intelligence or psychological warfare," he said.