Turkish President Recep Tayyip Erdoğan

ANKARA — Israel and Turkey announced on Monday they would normalize ties after a six-year rupture, a rare rapprochement in the divided Middle East driven by the prospect of lucrative Mediterranean gas deals as well as mutual fears over growing security risks.

Turkish Prime Minister Binali Yildirim said the two countries would exchange ambassadors as soon as possible.

The mending in relations between the once-firm allies after years of negotiations raises the prospect of eventual cooperation to exploit natural gas reserves worth hundreds of billions of dollars under the eastern Mediterranean, officials have said.

Israeli Prime Minister Benjamin Netanyahu said it opened the way for possible Israeli gas supplies to Europe via Turkey.

The move also comes as the Middle East is polarized by Syria’s civil war and as the rise of ISIS threatens regional security, leaving both countries in need of new alliances.

Relations between Israel and what was once its only Muslim ally crumbled after Israeli marines stormed an aid ship in May 2010 to enforce a naval blockade of the Hamas-run Gaza Strip and killed 10 Turkish activists on board.

Speaking after meeting U.S. Secretary of State John Kerry in Rome, Netanyahu said the agreement was an important step. “It has also immense implications for the Israeli economy, and I use that word advisedly,” he told reporters.

Kerry welcomed the deal, saying, “We are obviously pleased in the administration. This is a step we wanted to see happen.”

Netanyahu made clear the naval blockade of Gaza, which Ankara had wanted lifted under the deal, would remain in force.