The White House urged the chairman of the Securities and Exchange Commission to put on hold the sale of the Chicago Stock Exchange to a Chinese-led group, the Wall Street Journal reported on Thursday, citing people familiar with the matter.

SEC staff had wanted to approve the deal, but the new chairman, Jay Clayton, froze the agency’s decision last month, the report said, noting it is rare for commissioners to make such a move. The deal, seen by some as a Chinese takeover of the more than century-old exchange, has spurred political opposition, the report said.

A White House spokeswoman told the WSJ that the administration respected the SEC’s independence and doesn’t direct its actions.

The freeze means SEC commissioners will now have to vote on the deal, the WSJ said, but timing of the vote remains uncertain and the three commissioners could still approve the acquisition.

The White House and the SEC didn’t immediately return CNBC’s emailed requests for comment, which were sent outside office hours.

Read the Wall Street Journal’s full story on the SEC decision.