TOKYO—Israeli Deputy Prime Minister Ehud Barak called on Saturday during a visit to Japan for an "urgent" tightening of sanctions targeting Iran's oil exports and access to global financial clearinghouses, urging his Japanese hosts to put more pressure on Tehran to dissuade it from developing nuclear weapons.

"We have to increase the pace of imposing sanctions" on Iran's oil, central bank and access to international credit, Mr. Barak said at a news conference in Tokyo. "This should be done determinedly and in a conclusive...