Addressing a news conference in Washington on Thursday, Zoellick cautioned policymakers against moves based on populism and protectionism that could hurt the economy.

　　"I think it’s a mistake, and I think it’s a symptom that we have to watch out for, whether countries [under economic pressure] will move to more national, autarkic policies, [and] respond more to populism, respond more to protectionism," he said.

　　The Argentine government announced plans earlier this week to take over YPF, an Argentine unit of Spain's Repsol.

　　The government said the move was intended to boost oil output.

　　Spain has sharply criticized the plan.