Yahya related to me from Malik from Ibn Shihab from Salim ibnAbdullah that Abdullah ibn Umar used to say, "I pray the prayerof atraveller as long as I am undecided whether to remain somewhere ornot, even if I am detained for twelve nights."
USC-MSA web (English) reference: Book 9, Hadith 18
Arabic reference: Book 9, Hadith 346