Canada sending four pieces of field artillery to Ukraine as it braces for renewed Russian attack

Canada is expected to send four of its relatively new M-777 howitzers to Ukraine to help it face down a renewed Russian offensive from the east, CBC News has learned.

Prime Minister Justin Trudeau announced the plan to ship "heavy artillery" earlier this week, but offered no details on what the Canadian military would be donating.

"Their most recent ask was exactly for that, for heavy artillery, for reasons of operational security," Trudeau said on Wednesday. "I can't go into the details at this point on how and what we're getting to them exactly."

Three defence sources — who spoke to CBC News on the condition they not be identified because they were not authorized to speak publicly about the file — say four of the 37 howitzers Canada purchased during the Afghan war have been earmarked for shipment.

They will come out of the inventory of the 1st Regiment, Royal Canadian Horse Artillery, based in Shilo, Manitoba, said two of the confidential sources.

The shipment is expected to include an unspecified amount of ammunition, including precision-guided Excalibur rounds left over from the Afghan war, said a third source. The GPS-guided shells are worth about $112,000 US per round.

Canada recently shipped a portion of its aging stock of Carl Gustaf anti-tank weapons to Ukraine and the Liberal government has yet to announce a plan to replenish that stock with modern weapons.

Canada has been under pressure to provide heavy weapons as other allies continue to deliver more lethal aid, both overtly and quietly.

The U.S. announced this week it is donating 90 155mm howitzers as part of its recent $800 million US military aid package for Ukraine.

Those guns have started to arrive in Europe and American troops have begun training Ukrainian forces to use them, a senior U.S. defence official told several U.S. publications this week.

A U.S. official, quoted in the military publication Stars and Stripes, declined to say whether the U.S. is sending its M-777 or M-198 155mm howitzers. Both American cannons are of a different calibre than Ukraine's 152mm Msta-B howitzers.

The M-777 is a 155-millimetre towed howitzer. While it fires big shells, it was designed as an ultra-light gun by BAE Land Systems, Inc., a British arms maker, in the late 1990s.

The gun quickly became popular with the U.S. Army and Marine Corps and has been sold worldwide to a number of countries, most recently India.

Western armies like it because it's ideally suited for the kind of light, mobile warfare that took place in Iraq and Afghanistan. The gun can be easily and quickly transported by air — either slung under a helicopter and moved around the battlefield or stuffed into a large transport plane for rapid deployment to other countries.