Yahoo Inc. and Google Inc. may decide to call off their proposed partnership. The two Web search behemoths seem to prefer scrapping their plans for a strong and rich partnership than accepting government-imposed antitrust restrictions on it, two sources close to the companies’ discussions on the subject told Reuters.

Google and Yahoo have been working with Department of Justice officials to finalize the deal, but Google management seems to have lost its patience. The two Web search giants have been trying to convince the Justice Department officials that their plans to place Google ads next to Yahoo search results and share the earnings wouldn’t hurt the competition.

Although the partnership doesn’t need the Justice Department’s approval to go on, the agency has the means to block it and may very well do it.

"Are they more serious about walking away? Yes. Have they decided? I'm not sure," Reuters quoted a source familiar with the discussions between the companies. "Yahoo wants the deal, and they're willing to have Google sign anything at the Justice Department to have them do it."

The other source quoted by Reuters said that the two companies may announce that the deal is off as soon as Friday. Google and Yahoo representatives did not comment on the matter.

The two companies agreed on the partnership in June, but delayed its signing and implementation to give the U.S. Justice Department enough time to scrutinize it for antitrust issues. Considering the fact that the two giant companies had more than 80 percent of the web search market in August between them (comScore Inc stats), a partnership between the two should be scrutinized.

Microsoft has been the biggest critic of the partnership. The company argued that the deal would send 90% of search ads to Google, which already controls the Web search market.