Treasury Secretary Timothy Geithner will travel to China and Japan next week to discuss U.S. sanctions on Iran and the state of the global economy with top government officials, the Treasury Department said on Wednesday.

Geithner will meet with Chinese Vice Premier Wang Qishan on Tuesday and Chinese Premier Wen Jiabao on Wednesday.

He will travel to Japan on Thursday to meet with Japanese Prime Minister Yoshihiko Noda and Finance Minister Jun Azumi.

Geithner's trip is the latest step in an accelerating U.S. effort to reduce Iran's oil revenue and try to force the country to abandon its suspected nuclear weapons program. At the same time, the Obama administration wants to avoid a spike in crude prices that could threaten the global economy.

The Treasury Department said Geithner would discuss our continued coordination with international partners in the region to increase pressure on the government of Iran, including financial measures targeting the central bank of Iran.

President Barack Obama on Saturday signed into law new sanctions against financial institutions dealing with Iran's central bank, the main conduit for the country's oil revenues.

China, the No. 1 customer for Iran's oil, is unlikely to be swayed by the new U.S. law, analysts have said. China's Foreign Ministry on Wednesday restated Beijing's opposition to the U.S.-led push for unilateral sanctions on Iran.

In addition to the U.S. effort to tighten the financial screws, Iran faces the prospect of an outright European Union embargo on its oil. EU diplomats said on Wednesday that a preliminary agreement to ban imports of Iranian crude had been reached, and oil prices rose on the news.

Iran has warned it could choke off crude shipments through the Strait of Hormuz, a transit point for 40 percent of the world's oil, if sanctions were imposed. Many market participants, however, say the chance Iran will follow through with its threat is remote, and security analysts question whether it has the capability to shut the Strait.

A U.S. Treasury official said the Obama administration supported the EU proposal, adding that a phased-in effort to curtail use of Iranian crude could cut Tehran's revenues without disrupting oil markets.

During his trip to Asia, Geithner also will discuss policies to promote global economic growth and efforts to support a level playing field for global trade, the Treasury said.

The United States contends an undervalued yuan currency has given China a competitive trade edge, but the Obama administration, in a semi-annual report on currency practices last week, declined to name China a currency manipulator.

In the report, it said a faster appreciation of the Chinese yuan was needed. It also chided Japan for stepping into the currency market to stem the yen's rise.

(Editing by Tim Ahmann and Andrea Ricci)