Some people enter the mosque after the Iqama is called and give preference to praying the Fajr sunnah prayer. This causes some of them to miss one Rakah of the obligatory or even both Rakaas of Fajr.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

After the Iqaamah is called, no one should pray supererogatory prayers at that time. He should pray the mandatory prayer only. Abu Hurayrah narrated that the Prophet said: “When the Iqaamah is called, no prayer should be performed except the obligatory prayer.” [Muslim]

Besides, Al-Bukhari entitled a chapter in his Saheeh with the title: “No Salat (prayer) (is to be offered) except the compulsory Salat after the Iqamah has been pronounced for that compulsory Salat.”

The denial to perform such an act becomes greater when there is a risk to miss one Rak’ah of the obligatory prayer. The preponderant opinion of scholars is that this act is forbidden.

Allah knows best.