Is it permissible to perform Tayammum and pray when the muezzin calls the Fajr prayer while one is engaged in sexual intercourse?

The prayer of a person in a state of major ritual impurity (junub) is not valid before performing ghusl (ritual bath). Tayammum (dry ablution) is not sufficient for him if water is available and he is able to use it. Therefore, if the Fajr athan (call to prayer) is made while he is in a state of janabah, he must perform ghusl before praying. If there is not enough time for ghusl, he must perform ghusl and pray, even if it is after the prayer time has expired. If he is unable to use water due to illness or its unavailability, he is permitted to perform tayammum until his excuse is removed.