Israel and the Gulf state of Bahrain have reached a landmark deal to fully normalise their relations, US President Donald Trump has announced.
"The second Arab country to make peace with Israel in 30 days," he tweeted.
For decades, most Arab states have boycotted Israel, insisting they would only establish ties after the Palestinian dispute was settled.
But last month the United Arab Emirates (UAE) agreed to normalise its relationship with Israel.
There had been much speculation that Bahrain might follow suit.
The Gulf state has become only the fourth Arab country in the Middle East to recognise Israel since its founding in 1948. The others are Egypt and Jordan.
"Another historic breakthrough today!" Mr Trump wrote, adding: "Our two GREAT friends Israel and the Kingdom of Bahrain agree to a Peace Deal."
Prior to the UAE announcement in August, Israel had had no diplomatic relations with Gulf Arab countries. More recently, shared worries over Iran have led to unofficial contacts between them.