It's Canada's turn to host the North American Leaders' Summit, and security officials were actively planning for it to happen in February.
The last so-called Three Amigos summit was held in Mexico in February 2014. Canada hasn't hosted one since 2007, when it was held in Montebello, Que.
"President Obama and President PeñaNieto welcome Prime Minister Harper’s offer for Canada to host the next North American Leaders’ Summit in 2015," a joint declaration said last year.
In December, Canadian security officials learned the date would be changed to the fall. No further explanation was provided.
In a statement, the Prime Minister's Office said the summit will happen later in 2015.
"We have not announced a date for the meeting. We intend to host the meeting later in the year," said spokesman Jason MacDonald.
Summit dates prone to change
There is no fixed time of year for the three leaders to meet. Dates for the summit have been prone to change.
The three countries rotated hosting duties between 2005 and 2009, but in 2010, Canada postponed a meeting that had been scheduled to be held in Wakefield, Que., and then did not host it at all.
The summit scheduled for Hawaii in November 2011 was postponed following the sudden death of Mexico's interior secretary. U.S. President Barack Obama hosted his counterparts the following April in Washington.
There was no summit in 2013.
If the Harper government sticks to its fixed election date, the next federal election will be on Oct.19.
Although speculation is rife that the Conservatives may prefer to go to the polls early, the PMO has given no official indication that could happen.