Biden's visit is expected to focus heavily on Haiti, where Washington wants Canada to take the lead
The White House has said there is no indication three flying objects blasted out of the sky over the weekend by the US military are linked to alleged Chinese spying.
The US has shot down another unidentified flying object in the fourth military operation of its kind this month.
Nearly 100 million people in Canada and the US brace for some of the coldest air on earth, as a record-breaking deep freeze hits North America.
