US agricultural giant Monsanto said Tuesday that a raised takeover bid from Germany's Bayer was "insufficient," but that it remained open to talks to seal the transaction.

Monsanto said Bayer's bid last week of $125 per share, up from the prior $122 per share, was "financially inadequate" to ensure a deal. But Monsanto left the door open to talks, adding that there are no assurance a deal will be reached.