Order unanimously affirmed with costs. Memorandum: A party opposing a motion for summary judgment must produce evidentiary proof in admissible form sufficient to require a trial of material questions of fact on which he rests his claim (Zuckerman v City of New York, 49 N.Y.2d 557, 562). Defendant has failed to sustain its burden. Defendant's allegations regarding an alleged oral agreement with Charles R. Will, Jr., do not constitute proof in admissible form. Oral declarations or secret agreements between a mortgagor and an assigning mortgagee made prior to the assignment are inadmissible against the assignee to establish a defense to the action brought by the assignee to enforce the mortgage (Merkle v Beidleman, 165 N.Y. 21; 78 N.Y. Jur 2d, Mortgages, § 274). Additionally, a mortgage is a conveyance of an interest in real property and therefore falls within the ambit of the Statute of Frauds (see, General Obligations Law § 5-703; Sleeth v Sampson, 237 N.Y. 69).
Similarly, defendant has failed to produce evidentiary proof in admissible form to support its allegation that the mechanic's lien placed on the subject property was the result of fraud on Will's part. Conclusions or unsubstantiated allegations or assertions are insufficient as a matter of law to sustain defendant's burden (see, Zuckerman v City of New York, supra, at 562).