The Kremlin lifted its self-imposed ban on the delivery of a powerful missile air-defense system to Iran on Monday, stoking sharp criticism from the White House and Israel and casting fresh doubt on the international effort to curb Tehran’s nuclear program.

U.S. lawmakers seized on Moscow’s announcement Monday to warn Russia was among a host of foreign countries using the prospect of a nuclear deal to begin seeking out lucrative business deals that could bolster Iran’s military and economy.

...