Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) led the fear prayer at a place called Dhu Qarad. One row was behind him (peace and blessings be upon him) and the other row facing the enemy. Then he (peace and blessings be upon him) led them in one rak'ah. Then this row went to the place of the other row. Those came and prayed one rak'ah with the Prophet (peace and blessings be upon him). Then the Prophet (peace and blessings be upon him) gave the salam with them. Sufyan said: The Prophet (peace and blessings be upon him) had two rak'ahs, and each group one rak'ah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخوف / 6048