The bridge across the Narova River, which connects the Estonian town of Narva with Ivan-Gorod in Russia, is a major customs and border crossing point with around 150,000-200,000 trucks crossing it each year.
"The bridge has been closed for trucks with capacity over 3.5 tons as of today due to its unsafe condition," Valentin Sidorin, head of the administration press service, said, adding that trucks will now have to make a detour.
He said the decision to close the bridge had been made by the federal authorities.
The decision comes in the wake of Russian Railways railroad monopoly's move to cancel the St. Petersburg-Tallinn train service, citing financial considerations.
The service was only launched March 31, 2007. Five-car trains were used in a daily service carrying 16 to 45 passengers.
Russia's economics ministry said Tuesday it had no plans to limit trade with Estonia.
Some Russian politicians have demanded economic measures to punish the Baltic state for removing a Soviet-era war memorial from the center of its capital. The move triggered violent protests among Russian speakers in Estonia and youth rallies in Russia, and the two countries are continuing exchanging rebukes and threats.
Estonia's share in Russia's trade turnover is about 0.7%, with the former supplying sea products to Russia. Mineral resources, including oil and iron ore, make up 75% of Russian exports to the small Baltic nation, which also imports timber from Russia and is a crucial transit point for Russian energy supplies to Western Europe.
A handful of Russian companies have suspended their business ties with the ex-Soviet state over the dispute, but the government has not responded with sanctions against Estonia, whose business community is dominated by ethnic Russians.
But Tallinn could delay a $10.5-billion pipeline to pump gas from Russia to Germany on the Baltic Sea bed. Estonia and Finland have demanded a thorough environmental assessment of the ambitious project to eventually supply 55 billion cubic meters to Europe bypassing transit countries.
