Rules on Criminal Procedure
Section 7. Method of arrest by officer by virtue of warrant. - When making an arrest by virtue of a warrant, the officer shall inform the person to be arrested of the cause of the arrest and of the fact that a warrant has been issued for his arrest, except when he flees or forcibly resists before the officer has opportunity to so inform him, or when the giving of such information will imperil the arrest. The officer need not have the warrant in his possession at the time of the arrest but after the arrest, if the person arrested so requires, the warrant shall be shown to him as soon as practicable. (7a)