Book 20, Number 20.63.211:

Yahya related to me from Malik from Ibn Shihab from Said ibn al-Musayyab that Umar ibn al-Khattab prayed two rakas with everybody when he arrived in Makka. Then, when he had finished, he said, "People of Makka, complete your prayer, because we are a group of travellers." Later, Umar ibn al-Khattab prayed two rakas with them at Mina, but we have not heard that he said anything to them on that occasion.