Sayyiduna Imran bin Husayn (may Allah be pleased with him) said: I went on a campaign with the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) prayed only two rak'ahs until he returned to Madinah. I performed Hajj with him (peace and blessings be upon him), and he (peace and blessings be upon him) prayed only two rak'ahs until he returned. He stayed in Makkah for eighteen nights, praying two rak'ahs and saying: "O people of Makkah, complete your prayer, for we are travellers."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15607