OTTAWA, Dec 15 (Reuters) - Canada will advise citizens on Wednesday to avoid non-essential international travel to help reduce the threat from the Omicron variant of COVID-19, a government source said. The source, who requested anonymity because of the sensitivity of the situation, said the announcement would be made at a briefing but did not give more details. Prime Minister Justin Trudeau spoke with the premiers of the 10 provinces by phone on Tuesday to discuss ways of countering Omicron, which is spreading rapidly. A statement from Trudeau"s office said those on the call noted "the potential for a rapid and strong resurgence of COVID-19 cases in Canada that could put a strain on our health-care systems". Canada initially advised people not to travel abroad unless necessary in March 2020 but in late October this year withdrew the notice, citing the success of inoculation efforts. read more