Etobicoke MP Roy Cullen announced Thursday that he will not seek re-election during the next federal campaign, saying it is time "to start a new chapter."

"I feel it is time for new challenges, for me and my family, and for someone else to carry on the great Liberal tradition in Etobicoke North," Cullen said in a news release. 

Reports earlier this month quoted Cullen denying that he threatened to break ranks if Liberal Leader Stéphane Dion doesn't budge from his position that the combat component of Canada's Afghan mission should end as scheduled in February 2009.

Cullen was widely reported to have told a private caucus meeting that he won't support the leader's stance. The reports were based on anonymous party sources.

But Cullen's executive assistant sent an e-mail statement Feb. 8 to Liberal MPs, senators and parliamentary staff, saying Cullen did not threaten to vote against his leader.

Still, in a subsequent interview, Cullen did not promise categorically to support his leader.

The MP was first elected to the House in a 1996 by-election. He went on to win again in 1997, 2000, 2004 and 2006.

The current vice-chair of the House of Common' standing committee on public safety and national security, he also served as the Liberal's Natural Resources critic.

Cullen said he will continue to serve until the next election is called.

With files from the Canadian Press