What is the correct direction of praying in Masjid Al-Aqsa?

> There are two places where one can pray (uphold Salat) in any direction, one is Masjid al-Haram and the other is Masjid Al-Aqsa. Is this correct? If this is correct, is there any explanation about the reason that any direction is permitted inside them (other than Masjid Al-Aqsa being the first qibla)? (I would prefer answer with references to primary sources like Quran and/or Hadith).