JERUSALEM (Reuters) - Israeli Prime Minister Benjamin Netanyahu on Wednesday rebuffed criticism in Washington of his plans to speak in Congress, accusing world powers of forsaking a pledge to prevent Tehran from acquiring nuclear weapons.

"I respect the White House and the President of the United States but on such a fateful matter, that can determine whether or not we survive, I must do everything to prevent such a great danger for Israel," Netanyahu said in a speech.

He said world powers had pledged to prevent Iran from acquiring nuclear weapons, adding that "from the agreement coming together it appears they have given up on this commitment".

(Writing by Allyn Fisher-Ilan; editing by Andrew Roche)