Russian security forces were also involved in a raid on suspected militants in St Petersburg
Two gunmen have attacked traffic police on a road east of Moscow, injuring at least two officers before being killed by security forces, Russian media say.
The attack took place on the Shchelkovskoye highway in Balashikha, 20km (12 miles) from Moscow.
Police were investigating whether the men were from the North Caucasus area.
Russia has battled an insurgency in the region since two bitter separatist conflicts in its republic of Chechnya.
Separately, in St Petersburg on Wednesday, heavily armed Russian Special Forces conducted a raid on an apartment block, reportedly searching for North Caucasus militants.
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