Officials are monitoring the situation every hour, the official said.
Days after Arunachal Pradesh was put on high alert for possible flash floods after China informed India about the formation of an artificial lake in Tibet, a senior district official has allayed the fears of any eventuality.
Upper Siang Deputy Commissioner Duli Kamduk said no damage was reported in the district and the Siang river was flowing at the normal level.
This was also corroborated by Health and Family Welfare Minister Alo Libang, who is also the Yingkiong MLA.
Round-the-clock monitoring by senior district officials and National Disaster Response Force (NDRF) teams is on. However, the erosion of 50 metres of land by the river was reported from the Mebo area on Sunday.
The erosion by the river was still continuing, Mebo MLA Lombo Tayeng said.
People living along the banks of the Siang river were moved to safer places after China informed India about possible flash floods in the north-eastern state, officials had said Saturday.
The first rush of water had reached Pasihgat, the headquarters of East Siang district in Arunachal Pradesh, at around 7.30 am Saturday.
Chinese Embassy spokesperson Counselor Ji Rong had said his country had activated the "Emergency Information Sharing Mechanism" with India, following the landslide Wednesday morning near Jiala village in Milin County in the lower ranges of the Yaluzangbu river in Tibet.
The reason cited behind the landslide was "natural causes". The Yaluzangbu river is called Siang when it enters Arunachal Pradesh and Brahmaputra in Assam.