Amr bin Dinar (may Allah have mercy on him) narrates from Abu Fakhitah, who said: I heard Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) saying: Only one who is fasting may stay (in i'tikaf).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8582