Is it permissible to pray the Fajr rawatib while the imam is praying the obligatory prayer?

The questioner : May Allah reward you with good. He says:The questioner : Some people pray the two rak'ahs of Fajr while the imam is praying. Is this action permissible?

The Shaykh : It is not permissible for a person to pray the two rak'ahs of Fajr while the imam is praying, because the Prophet (peace and blessings be upon him) said: However, if a person enters the two rak'ahs before the iqamah is called and reaches the second rak'ah, meaning he stands up for the second rak'ah, let him complete it briefly, as it is originally brief. And if the iqamah is called while he is in the first rak'ah, let him break off so that he can join the imam. Then, when the imam's prayer is finished, he makes up the missed prayer afterwards.