The Obama administration on Thursday invoked US law to sanction China's State-run Zhuhai Zhenrong Corp, barring it from doing business in the US.

"Like many other countries, China maintains normal cooperation with Iran in energy, the economy and trade," Foreign Ministry spokesman Liu Weimin said in a statement issued on the ministry's website late on Saturday.

The US is attempting to internationalize its unilateral sanctions against Iran, and to implement sanctions against a Chinese company according to its domestic law, Liu said.

"This is without reason, and against the content and spirit of resolutions of the United Nations Security Council on the Iran nuclear issue," he added.

The sanctions, also placed on companies from Singapore and the United Arab Emirates, bar the three firms from receiving US export licenses, trade support from the US Export Import Bank, and loans over $10 million from US financial institutions.

Zhuhai Zhenrong spokesperson Zheng Mei said on Friday the US sanctions were "truly puzzling", as the company has never exported refined petroleum as Washington alleged, according to the Legal Mirror newspaper.

The firm will continue to import oil from Iran, Zheng said, adding the sanctions don't make any difference to the company because it has never had any business dealings with any US companies.

US President Barack Obama last month signed into law new unilateral sanctions targeting Iran's central bank and financial sector. Diplomatic campaigns have been launched to persuade other countries to join its sanctions against Iran.

The European Union is expected to make a decision on an oil embargo on Iran at a Jan 23 meeting. But an official close to the talks said that the EU probably will not embargo Iranian oil until the summer, according to The Associated Press.

Japanese Prime Minister Yoshihiko Noda said on Friday that Japan had yet to decide whether it would reduce oil imports from Iran, continuing to send mixed signals in response to the US request to join in the sanctions, according to The New York Times.

A senior Indian cabinet minister also said on Thursday India will keep doing business with Teheran, Reuters reported.

Jin Canrong, deputy dean of the School of International Studies at Renmin University of China, said the US is currently obsessively self-centered, and often forces other countries to do what they are unwilling to do.

"It is already difficult for the US to negotiate with its smaller allies, and even harder to negotiate with independent nations. Therefore, its final attitude very likely will fall short of its requirement," Jin said when interviewed by China Radio International.

"It is understandable for the US to have its concerns, but if it adopts a fierce campaign, it will also offend other countries," Jin added.