Is it permissible for a Muslim to perform Umrah after passing the Miqat, remain in Makkah, and then perform the obligatory Hajj?

It is permissible for a Muslim to enter into a state of ihram for Umrah only from the miqat, then to exit ihram and remain in Makkah to enter into ihram for Hajj from his location in Makkah on the eighth day of Dhul-Hijjah. This is called Hajj at-Tamattu, and it is the best of the rituals. The mutamatti is obligated to sacrifice an animal (hady) in Makkah. If he cannot find one, then he must fast three days during Hajj and seven after returning to his country, based on the words of the Almighty: (So whoever performs Umrah [in the months of Hajj] then [proceeds to] Hajj - whatever can be obtained easily of sacrificial animals. But if he cannot find [one] - then a fast of three days during Hajj and seven when you have returned [home]. Those are ten [days] complete). It is also permissible to perform Hajj al-Ifrad (intending Hajj only, with no hady required) or Hajj al-Qiran (intending both Hajj and Umrah together from the miqat, not exiting ihram between them, and a hady is obligatory for him, like the mutamatti).