Canadian Oil Sands Ltd. declared victory Monday by saying its shareholders overwhelmingly rejected a hostile takeover bid from rival Suncor Energy Inc.

"Our board has heard the message Canadian Oil Sands shareholders have sent loud and clear in overwhelmingly rejecting Suncor's hostile bid and the value you place on the assets you own," Chairman Donald Lowry said in a statement.

Suncor in late 2015 made a hostile bid to acquire all stocks in Canadian Oil Sands. Both companies are stakeholders in the Syncrude oil sands processing facility in Alberta, though Canadian Oil Sands holds the most shares in the operation.

Both companies in recent days have issued statements touting the benefits of their respective positions. Canadian Oil Sands said Suncor's bid was an opportunistic one, given the financial pressures from lower crude oil prices. Suncor countered that it would be in a better position to return value to shareholders if it were in the lead.

Canadian Oil Sands said Suncor now has an obligation to disclose details of how shareholders reacted to the $3 billion offer.

"We believe there is a fundamental disconnect between what Suncor led the market to believe they would have and what they actually have," Lowry said. "Suncor can now be transparent to our shareholders by disclosing the exact amount tendered."

Suncor countered by extending the deadline for its bid for a third time. The last deadline lapsed Jan. 8 and the company said it was extending the offer to Jan. 27. CEO Steve Williams said the extension was meant to give shareholders more time to emerge in favor of the deal.

"We are encouraged by the number of shares that have been tendered," he said in a statement.