Beijing is buying less Iranian crude this month, but analysts say China is unlikely to support an oil embargo. Instead, they say, the smaller purchases might be a tactic aimed at obtaining lower prices as the West squeezes Tehran.

The sanctions approved by President Barack Obama on New Year's Eve have highlighted the importance of Iranian oil supplies to East Asia's energy-hungry economies. They have led to a clash of interests between Washington and key commercial and strategic partners over efforts to stop Iran's nuclear program.

"We are considering our response and are closely discussing the matter with the U.S.," a Japanese Foreign Ministry official, Kazuhiro Kawase, said Friday.

A South Korean Foreign Ministry spokesman said this week Seoul is in talks with Washington aimed at "minimizing the negative impacts" of sanctions. South Korea imports 97 percent of its oil and depends on Iran for up to 10 percent of its supplies.