"I want to congratulate President Trump on the impressive achievement of bringing about the elimination of al-Baghdadi," Netanyahu said on a visit to an Israeli air force base in remarks broadcast by army radio.

"This reflects the united resolve of the free countries led by the United States to fight the forces of terror, the terror organisations and the terrorist states," a later statement from the premier's office quoted him as saying.

"This is an important milestone, but it's part of a longer battle which me must win."

Trump said earlier that Baghdadi died "like a dog," in a daring, nighttime raid by US special forces deep in northwest Syria.

In a televised address from the White House Trump said that US forces killed a "large number" of Islamic State group militants during the raid which culminated in cornering Baghdadi in a tunnel, where he set off a suicide vest.

He said that the raid -- which required flying more than an hour by helicopter in both directions from an undisclosed base -- had been accomplished by help from Russia, Syria, Turkey and Iraq.