OTTAWA  |  Thu Apr 23, 2015 9:19pm BST

Canada, heavily criticized over its environmental record, will need to introduce new regulations to meet updated international climate change targets, Prime Minister Stephen Harper said on Thursday.

Harper, who has already ruled out a federal carbon tax and Canada-wide measures against the booming oil and gas sector, did not give details.

Recent data shows Canada has no chance of meeting its original 2020 target for cutting greenhouse gas emissions by 17 percent below 2005 levels unless it takes further steps.

The United Nations is planning a summit in Paris in December to agree cuts beyond 2020. Harper says he will present Canada's updated targets in May.

The United States plans emissions cuts of up to 28 percent below 2005 levels by 2025.

"It's unlikely our targets will be exactly the same as the United States but they will be targets of similar levels of ambition to other major industrialized countries," Harper told a televised news conference in Winnipeg.

"Broadly speaking, there will have to be additional regulatory measures going forward to achieve these targets," he added.

Pressed as to what Harper might have been referring to, a spokeswoman for the prime minister promised to respond later in the day.

Leaders of nine Canadian provinces and territories called on Harper earlier this month to take stronger measures to cut greenhouse gas emissions by 2050.

Green groups say Canada is not serious about combating climate change and note the continued failure to act against the oil and gas sector.

The right-of-center Conservatives, whose political heartland lies in the energy-rich west of Canada, came to power in 2006 and quickly promised to impose regulations on oil and gas producers to reduce greenhouse gases.

But last December Harper changed course, saying it would be crazy to go ahead with the regulations without simultaneous action from the United States.