Arizona Sens. John McCain and Jon Kyl are calling on State Department official Michael Posner to formally apologize for expressing regret about Arizona's immigration law to a Chinese delegation last week during a discussion on human rights.

"Comparing the Arizona law to what takes place in China is an absolute outrage," McCain told Fox News.

The two Republican senators wrote a letter to Posner Tuesday calling his remarks "particularly offensive" and demanding that he retract his statements.

That was after Posner told reporters Friday that a U.S. delegation, meeting with Chinese representatives for two days in Washington, brought up the Arizona law "early and often" as an example of a trouble spot Americans need to work on.

"It was mentioned in the first session, and as a troubling trend in our society and an indication that we have to deal with issues of discrimination or potential discrimination, and that these are issues very much being debated in our own society," Posner said.

Under fire for the comment, the State Department backed him up on Tuesday. Spokesman P.J. Crowley said the Arizona law would pose a "fundamental challenge to human rights around the world" should it lead to racial profiling.

Posner also told Foreign Policy's blog The Cable that his remarks were taken out of context. He said the "broader context" was that the issue was raised to discuss the "political openness of this society." He said he "should have been clearer," but that "we never did get into the merits of the Arizona law."

"It was not in any way a comparison between that law and any specific law or practice in China," Posner told The Cable.

A few lawmakers, though, took Posner's comments as an attempt to equate the immigration policy with China's documented human rights abuses.

"To compare it with the human rights abuses that take place in China ... it's so irresponsible," McCain told Fox News.

Kyl and McCain wrote in their letter to Posner that China's record is "only worsening" based on the State Department's own analysis.

"Your bureau's report details how democracy activists, religious groups, journalists, and human rights advocates in China continue to be 'targeted for arbitrary arrest, detention, and harassment.' The report also describes the brutal tactics the Chinese regime uses to suppress these peaceful groups," they wrote.

"To compare in any way the lawful and democratic act of the government of the state of Arizona with the arbitrary abuses of the unelected Chinese Communist Party is inappropriate and offensive."