Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Sahl bin Sa’d (may Allah be pleased with him) that when he was fasting, he would order a man who would climb to a high place. When he said that the sun had set, the Prophet (peace and blessings of Allah be upon him) would break his fast.

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that when the Prophet (peace and blessings be upon him) was fasting, he would break his fast before performing the Maghrib prayer, even if it was with a sip of water.