Timothy Geithner will travel to China a Japan next week to discuss tougher sanctions against Iran, the US Treasury Department said Wednesday, hours after China said it opposed unilateral US measures.

In a statement, the Treasury Department said Geithner would visit the two Asian economic powers in a January 10-12 trip.

In China he will meet Chinese Premier Wen Jiabao and Vice President Xi Jinping. In Japan he will meet Prime Minister Yoshihiko Noda.

Geithner will discuss "discuss the state of the global economy, policies to strengthen global growth and other economic issues of mutual importance," the statement said.

"Secretary Geithner will also 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."

Earlier on Wednesday China said it opposed "unilateral" sanctions against Iran, after US President Barack Obama signed into law new measures targeting the Islamic Republic's central bank.

Washington's move came after the United States, Britain and Canada said in November they were slapping additional sanctions on Iran, citing evidence that Tehran is pursuing nuclear weapons.

Tehran denies the allegations, saying its nuclear program is exclusively for medical and power generation purposes, and China has repeatedly said sanctions will not resolve the issue.

"China opposes placing one's domestic law above international law and imposing unilateral sanctions against other countries," said foreign ministry spokesman Hong Lei when asked about US sanctions on Iran.

Geithner's visit will also come days after his department rapped China and Japan for allegedly unfair currency interventions.

In the dying days of 2011 the Treasury Department issued a report warning China its yuan is still significantly undervalued.

But it refrained from saying Beijing manipulates the currency -- which could lead to retaliatory action by Congress.

"The real exchange rate of the renminbi is persistently misaligned and remains substantially undervalued, though the degree of this undervaluation appears to have declined significantly," the Treasury said in a semi-annual report to Congress.

The report also criticized Japan's efforts to keep the yen from appreciating amid global foreign exchange market turmoil.

US lawmakers urge probe of telecom firms in Iran
Washington (AFP) Jan 5, 2012 - The US State Department said Thursday it was mulling a request from US lawmakers to probe whether China's Huawei Technologies and other telecom firms are violating US sanctions on Iran.

Last month, six lawmakers sent a letter to Secretary of State Hillary Clinton, urging her to look into press reports that Huawei had sold technology to Iran allowing Tehran to monitor people's locations via their cell phones.

"Such services may be a critical tool for the Iranian government in disrupting and restricting the speech of its people," said the lawmakers, including senior Republican Senator Jon Kyl.

Spokeswoman Victoria Nuland told reporters on Thursday that the State Department had received the letter, dated December 22, and was "following up on it."

"This is a complex issue. It's going to take time," Nuland said.

"As we have already explained to the Chinese government, if we assess that the company involved was engaged in sanctionable activity involving the export of technology to Iran... we will have to take appropriate action."

Huawei, founded by a former People's Liberation Army engineer, produces technology that is used to build mobile phone networks around the world. It has repeatedly denied any links to the Chinese military.

The lawmakers hailed Huawei's decision, announced last month, to scale back its activities in Iran, due to what the Shenzhen-based company called the "increasingly complex situation" in the Islamic republic.

But it warned that the company's "previous actions and continuing service of existing service with Iranian clients may violate" US sanctions.

US sanctions bar any company exporting sensitive telecommunications technology to Iran from entering into a contract with the US government.

The lawmakers cited a report in the Wall Street Journal which said other firms including Telefon AB L.M. Ericsson and Nokia Siemens Networks also provided technology to Iranian carriers that could be used for monitoring.

Another report from Bloomberg, cited by the lawmakers, also named Creativity Software Ltd. and AdaptiveMobile Security Ltd. as marketing or providing similar technology to Iranian state-run telecom operators.

The lawmakers said that if the State Department were to identify companies in violation of US sanctions, it would "send a powerful message to the commercial accomplices of the Iranian regime that their actions will not go overlooked."