锡尔河
The Ak-Suu () is a left tributary of the Syr Darya, flowing through Batken Province of Kyrgyzstan and Sughd Province of Tajikistan. The river is formed at the north slopes of Turkestan Range in Sarkent State Nature Park. It flows into the river Syr Darya near the town Nau in northern Tajikistan. The main settlements at the river are the village Ak-Suu in Kyrgyzstan and the town Nau in Tajikistan.