The dollar rose on Monday along with the yen and the Swiss franc as investors rushed into safe-haven assets amid fears that Russia is preparing to invade Ukraine. The move came a day after the United States said Russia could attack Ukraine at any time. Russia has denied having any such plans though a senior official said it was ready to fire on foreign ships and submarines that illegally enter its waters. The dollar index rose 0.4 percent to 96.351, its highest since Feb. 1, at 1133 GMT. Euro-dollar one-month implied volatility was at 7.45 percent, the highest since November 2020, from below 6 percent at the end of January. The rouble was flat at 77.08 against the dollar, after tumbling to its lowest since Jan. 28 on Friday as investors ditched Russian assets. “European dependency on Russian energy makes the cyclical economic performance of the [eurozone]  particularly vulnerable in …