JERUSALEM — Prime Minister Benjamin Netanyahu of Israel warned on Sunday that his nation would ensure that Tehran never obtains nuclear weapons, while also taking credit for keeping Iran from already having them.

Mr. Netanyahu has been an open and vocal opponent of the deal with Iran. Speaking at the start of the regular weekly cabinet meeting, Mr. Netanyahu said, “Israel’s policy has been and will remain exactly what it has been: not to allow Iran to acquire nuclear weapons.”

He also said that the recent accord would strengthen and embolden Iran’s leaders, since the lifting of most sanctions would free up money for Tehran to arm and support the government of President Bashar al-Assad in Syria, Shiite militias and Israel’s enemies in the region, including Hezbollah, Hamas and Islamic Jihad.

“What is clear is that Iran will now have more resources to dedicate to their terrorism and aggression in the region and in the world, and Israel is prepared to deal with any threat,” he said.