The inauguration of the bridges, built by the Border Roads Organisation (BRO) comes at a time when India and China are engaged in a border row in eastern Ladakh.
The Indian and Chinese armies are locked in the standoff in multiple locations in eastern Ladakh for the last seven weeks.
Twenty Indian soldiers lost their lives in a violent face-off in Galwan valley on June 15-16 after an attempt by the Chinese troops to unilaterally change the status quo during the de-escalation.
According to rules of the United Nations, all areas extending up to 12 nautical miles from a country's coastline are its territorial waters (TW).
Singh arrived here on a three-day visit on Tuesday at the invitation of the Russian Ministry of Defence to attend the celebrations.
It is the first visit abroad by a senior union minister in four months as foreign travels were restricted in view of the coronavirus pandemic.
It is learnt that the Army has been advised by the Defence Minister to be very cautious during patrol duty and enhance strict vigil at the border with China.
The defence minister's visit comes in the midst of escalating border standoff between India and China, particularly after the killing of 20 Indian Army personnel by Chinese troops in eastern Ladakh.
The Indian Army on Tuesday said 20 Army personnel, including a Colonel, were killed in the clash on Monday night, in the biggest ever military confrontation between the two armies.
In a virtual rally for Uttarakhand, Singh underscored the deep ties between the two countries, saying they were bound together by 'roti and beti', and no power in the world can break it.
Singh also assured the opposition that the central government will not keep Parliament or anyone in the dark about developments on the border and will share details at an appropriate time.
"The border dispute between India and China has been ongoing for a long time. We want to resolve it as soon as possible," Singh said.
The talks are continuing at the military level and I understand a senior military officers level talk possibly will take place on 6 June, Army Chief informed me today, said Singh.
The 'missing' posters of Rajnath Singh were put up on Saturday afternoon in Saadatganj, Para, Thakurganj and Talkatora areas.
Earlier, Rajnath Singh chaired a meeting with the three service chiefs and the Chief of Defence Staff General Bipin Rawat.