Russia on Saturday said it was "extremely concerned" about the build-up of troops on the India-Pakistan border, warning that tensions between the two nuclear foes had reached a dangerous level. "Russia is extremely concerned by the news that on both sides of the border there is a build-up of troops and military equipment," the foreign ministry said in a statement. "The tension in this region has reached a dangerous level. There are worrying reports that New Delhi and Islamabad are not ruling out the use of force against each other," it added. "Russia calls on India and Pakistan to show the maximum restraint and not allow the situation on the border to develop into one of force," it added, saying that negotiations were the only way out of the crisis.