Yahya related to me from Malik from Hisham ibn Urwa from his father that the Messenger of Allah, may Allah bless him and grant him peace, prayed four raka prayers with only two rakas when at Mina, and that Abu Bakr prayed them at Mina with only two rakas, and that Umar ibn al-Khattab prayed them at Mina with only two rakas, and that Uthman prayed them at Mina with only two rakas for half of his khalifate, and then later completed them.
Muwatta Malik Book 20, Hadith 213
← Previous Hadith Malik said that the people of Makka who are doing hajj should shorten the prayer to two rakas when at Mina until they go back to Ma ka.

Muwatta Malik Book 20, Hadith 212 Next Hadith → 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.

Muwatta Malik Book 20, Hadith 214