Commodore John D. Sloat, commander of the U.S. Navy's Pacific Squadron, near Mazatlan, Mexico, had received orders to seize San Francisco Bay and blockade California ports when he was positive that war had begun. Sloat set sail for Monterey, reaching it on July 1. On 5 July, Sloat received a message from Capt. John B. Montgomery of the Portsmouth in San Francisco Bay reporting the events of the Bear Flag Revolt in Sonoma and its open support by Brevet Capt. John C. Frémont. In a message to Montgomery, Sloat relayed his decision to seize Monterey and ordered the commander to take possession of Yerba Buena (San Francisco), adding, "I am very anxious to know if Captain Frémont will cooperate with us." On July 9, 70 sailors and Marines landed at Yerba Buena and raised the American flag. Later that day in Sonoma, the Bear Flag was lowered, and the American flag was raised in its place.