Israel's security agencies are stepping up targeted attacks throughout the world on Hamas' leadership in what one Israeli official called "intelligence-based prevention."

In the past two months, Israeli operatives have intercepted a German ship in international waters, fired a missile at a suspected Hamas leader in Sudan, and captured a Hamas engineer in the Ukraine, according to Israeli and Western officials and press reports from the region.

"Israel defeated the wave of suicide bombing attacks against it in 2002 by identifying the leadership that was behind it and making it clear to them that they would pay a price," said Dore Gold, a former Israeli ambassador to the United Nations and specialist on international terrorism.

"Presently, the effort to cripple Hamas' military capabilities is no longer confined to the Gaza Strip alone, but to the entire Hamas global network and that of its allies."

On Thursday, an anti-tank rocket hit an Israeli school bus near the Gaza border and wounded two people. Israeli planes and tanks fired at Hamas positions in Gaza on Thursday in retaliation.

After a day of Israeli attacks that reportedly killed five Palestinians, Hamas issued a statement offering a cease-fire. The Interior Ministry told reporters in Gaza that militant groups had agreed to stop firing rockets.

The Israeli military had no immediate public comment.

But the overt warfare might end there for now; still, the security services will keep up their secretive work.

"This is a policy of intelligence-based prevention, which has stepped up in recent months," an Israeli national security official, who asked not to be named, told The Washington Times. "One part of the strategy is prevention."

While Israelis have conducted intelligence operations throughout the world for years, these kinds of direct actions have become more central to Israel's war policy against Hamas under Prime Minister Benjamin Netanyahu.

"Our security requirements are fundamental … for the achievement of peace," Mr. Netanyahu said after talks Thursday with German Chancellor Angela Merkel in Berlin.

"But they're particularly important now in this uncertain period that we're going through."

The Arab world has been in turmoil since January, with the Libyan civil war the latest in the unrest that has Israel nervous.

"We can't be sure … if this is [like] an 1989 change in Europe or the 1979 revolution in Iran," Mr. Netanyahu said, referring to the fall of communism in Europe and the rise of the Islamic terrorism in Iran.

The renewed Israeli approach is in some ways a response to the international condemnation of Operation Cast Lead, the Israeli air-and-ground offensive against Hamas positions in Gaza launched in December 2008.

Operation Cast Lead claimed between 1,166 and 1,417 Palestinian casualties. Israel says Hamas deliberately interspersed its military positions in civilian neighborhoods in hopes that Israeli attacks would kill civilians and that Hamas could wage a propaganda war against the Jewish state.

The 2008-09 Gaza war prompted the U.N. Human Rights Council to appoint Richard Goldstone, a South African jurist, to investigate the war. He at first concluded that Israel deliberately targeted Palestinian civilians.

Mr. Goldstone recanted that charge last week in an Op-Ed for The Washington Post.

Because the covert campaign targets leaders and is often done in secret, the diplomatic damage to Israel for these actions tends to be muted.

The first example of this new tactic against Hamas happened in January 2010, when a Mossad team killed Mahmoud al-Mahbouh, a senior Hamas operative, in a Dubai hotel.

More recently, Israeli operatives in February captured Dirar Abu-Sisi, a Hamas engineer Israel accuses of designing military rockets for the group, aboard a train in the Ukraine, according to Israeli court documents unsealed Monday. Mr. Abu-Sisi told Israeli reporters he was innocent Monday.

On Tuesday, an unidentified aircraft fired a missile at a car carrying two men in Sudan. Israeli officials publicly neither confirmed nor denied any role in the operation.

However, a Hamas member of parliament, Ismail al-Ashqar, said this week that the attack was aimed at his nephew, Abdel Latif al-Ashqar, a Hamas commander, according to the Gaza based Safa news service. The government of Sudan has also said Israel was behind the missile attack.

In March, Israeli commandos boarded the Victoria, a German ship carrying Chinese-made land-to-sea rockets. Mr. Netanyahu said the ship was from Iran and headed eventually to Gaza.

Lt. Col. Avital Leibovich, an Israel Defense Forces spokeswoman, said, "We are not looking only for Hamas leaders, we consider Hamas accountable for any rockets fired from Gaza into Israel. If we find a three-man rocket team, they will be targeted whether or not they are leaders. This is to prevent rockets from coming down on Israeli civilians."

Col. Leibovich added that every attack in Gaza is authorized by a military lawyer and is "accordance with international law."

"We are not looking for any escalation," she said. "We do have operational plans in our drawers. Hopefully, we won't have to pull them out, but we will not tolerate these kinds of attacks against Israeli civilians."

The Israeli national security official, however, said there would be a steep price Hamas will pay if Israel determines that Hamas deliberately fired at an Israeli school bus.

"If this turns out this was a premeditated attack, that this was a planned decision to fire a rocket on a school bus, this is something we will have to not only counter but also make Hamas understand this action's consequences," the official said.