OTTAWA - Liberal reaction to the Conservatives' new citizenship guide has unleashed a battle over semantics that led Justin Trudeau to issue an apology of sorts.

The government published its new citizenship guide on Monday, including a mention that Canada accepts gay marriages and respects gay and lesbian rights -- facts that were omitted in an earlier draft.

But Trudeau, the Liberal immigration critic, is drawing controversy for his response to another element of the guide: its description of honour killings as a "barbaric" cultural practice.

Trudeau argued that the government should have qualified violence against women as "absolutely unacceptable" instead of belittling other cultures with the word "barbaric."

His argument immediately set off howls of protest from Conservative bloggers, the Prime Minister's Office and the immigration minister.

Their condemnations and the subsequent fallout online brought about an apology from Trudeau, who called all violence against women barbaric.

"My Liberal critic says the Government should exercise 'responsible neutrality' in discussing honour killings," Immigration Minister Jason Kenney said via Twitter on Monday night.

"Liberal cultural relativism is precisely what undermines public support for multiculturalism. Its (sic) wrong & irresponsible."

Trudeau defended himself on Twitter early Tuesday morning.

"My problem with the use of the word barbaric is that it was chosen to reassure Canadians rather than actually change unacceptable behaviours," he said.

"I suggested 'totally unacceptable' off the top of my head. Clear, strong, and objective, without being 'us civilized, you not."'

Trudeau told the PMO that he believes honour killings are barbaric, but "my issue is with tone and target audience in regards to the guide."

But as mockery of Trudeau's comments exploded online, he eventually conceded he may have been misinterpreted.

"Ok, final word: all violence against women is barbaric. If my concerns about language led some to think otherwise, then I gladly apologize," Trudeau tweeted.

NDP immigration critic Olivia Chow did not immediately wade into the debate.