Rabi'ah bin Abdullah (may Allah have mercy on him) saw Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) removing ticks from his camel in the mud at al-Suqya; and in the narration of al-Muwatta they added: "while he was in the state of ihram."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10059