Salah should be performed after the Adhan according to the saying of the Prophet (peace be upon him),
There is a prayer between each two calls (Adhan and Iqamah).
And according to his saying,
May Allah have mercy on a man who performs four Rak`ahs before Al-`Asr (Afternoon) Prayer.
Therefore, it is desirable for a person to offer two or four Rak`ahs according to the two Hadith mentioned above, however this is not obligatory upon him.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.