When the prime minster called a hasty press lock-up on a Friday evening, Ottawa knew something big was brewing.

Stephen Harper has announced the government's approval of the hotly-contested takeover of Calgary-based energy company Nexen by state-run Chinese firm CNOOC. Also approved is the takeover of Progress Energy Resources Corp. by Petronas, Malaysia's oil and gas giant.

State-owned companies investing in Canada's energy sector has proved a very divisive topic and criticism from the opposition was fast and furious.

Not long after's Harper's announcement, Nathan Rotman, National Director of the NDP, sent an email to supporters saying that the prime minster had "just sold us out."

"I can’t believe it," he said. "Just moments ago, Stephen Harper sold out our natural resources ... This entire deal was made behind closed doors. No public hearings. No transparency. And now this — an announcement at 5 p.m. on a Friday."

"Today they're trying to sugar-coat something that I think will be a rather bitter pill,'' New Democrat natural resource critic Peter Julian told the Canadian Press, adding that there should have been more consultation with Canadians. "This is a farce."

Critics were also quick to jump on Harper's insistence that the CNOOC-Nexen approval was "exceptional" and foreign takeovers will face more scrutiny going forward.

Green Party leader Elizabeth May tweeted that it was a "clever move" to approve the deal and say "never again."

See reaction from politicians, journalists and readers:

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• TheHarperGovernment

  The good news is that Alberta does not have to impose a one-child policy until 2020. #cnooc #nexen #cdnpoli

• Anita Sharma

  @ammoe1993 These deals with CNOOC and Petronas have certainly had our newsrooms engaged in heated debate for months...

• robert lavigne

  Jack Mintz cheerleads the CNOOC deal .. umm how about a good read first Jack ..?? or were you in on the discussion ..?

• Brett R. Harvie

  Looks like the #CPC & @pmharper struck an appropriate balance on the Nexen/Progress decision. #cdnpoli

• *CaptainRon*

  Looks like #Harper will secure himself a 'lifetime job' in the oil fields of #China in #Canada #Nexen

• Bryan Borzykowski

  I want to talk to that person or persons who sold all that Nexen stock an hour and a half ago. #callme

• Nathan Rotman

  Why future restrictions on foreign takeovers. Protect Canadian jobs and environment now. #nexen #cdnpoli

• Danno

  Hey Harper! You seem to have forgotten you are Prime Minister of Canada. Not Israel. Not China. C-A-N-A-D-A #PnPCBC #cdnpoli #Nexen #Cnooc

• TheHarperGovernment

  We have been concerned for sometime abt SOEs but were utterly unprepared and just winged this one. #cnooc #nexen #cdnpoli

• Vassy Kapelos

  When we say that Canada is open for business, we do not mean that Canada is for sale to foreign governments - Harper #cdnpoli #cnooc #nexen

• Nancy Leblanc

  Harper not commenting on details of Nexen takeover, i.e., the undertakings. How can we be assured it's a good deal then?

• Chris McLeod

  Harper's decision on Nexen and Petronas prove that our country and our economy is in sound hands with the Conservative Party. #CdnPoli

• Carrick Irwin

  I think all #Canadians should divest in #Nexen as of this moment. #cdnpoli

• Andrew Coyne

  It's just embarrassing to see someone who knows better spool out this gibberish. #nexen

• Joe Fantauzzi

  That time the Tories, after slamming the opposition as "socialists", sold off parts of the tar sands to a communist regime...#cdnpoli #nexen