Sayyiduna Abdullah bin Amr (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Gog and Magog are from the children of Sayyiduna Adam (peace be upon him). If they were let loose, they would ruin people's livelihoods. None of them dies until he leaves behind a thousand or more of his descendants. And after them there are three nations: Tawil, Taris and Mansak."
Al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat, and its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفتن - أعاذنا الله منها / 12571