Title II — TAX ON INCOME such credits in the year in which the taxes of the foreign country accrued, the credits for all subsequent years shall be taken upon the same basis, and no portion of any such taxes shall be allowed as a deduction in the same or any succeeding year. (7) Proof of Credits. — The credits provided in Subsection (C)(3) hereof shall be allowed only if the taxpayer establishes to the satisfaction of the Commissioner the following: (a) The total amount of income derived from sources without the Philippines; (b) The amount of income derived from each country, the tax paid or incurred to which is claimed as a credit under said paragraph, such amount to be determined under rules and regulations prescribed by the Secretary of Finance; and (c) All other information necessary for the verification and computation of such credits. (D) Losses. — (1) In General. — Losses actually sustained during the taxable year and not compensated for by insurance or other forms of indemnity shall be allowed as deductions: (a) If incurred in trade, profession or business; (b) Of property connected with the trade, business or profession, if the loss arises from fires, storms, shipwreck, or other casualties, or from robbery, theft or embezzlement. The Secretary of Finance, upon recommendation of the Commissioner, is hereby authorized to promulgate rules and regulations prescribing, among other things, the time and manner by which the taxpayer shall submit a declaration of loss sustained from casualty or from robbery, theft or embezzlement during the taxable year: Provided, however, That the time limit to be so prescribed in the rules and regulations shall not be less than thirty (30) days nor more than ninety (90) days from the date of discovery of the casualty or robbery, theft or embezzlement giving rise to the loss. (c) No loss shall be allowed as a deduction under this Subsection if at the time of the filing of the return, such loss has been claimed as a deduction for estate tax purposes in the estate tax return. (2) Proof of Loss. — In the case of a nonresident alien individual or foreign corporation, the losses deductible shall be those actually National Internal Revenue Code of 1997 (as amended by the TRAIN Law, RAs 11256, 11346 and 11467) 49