MOSCOW — The two powerful explosions that tore through Moscow’s subway on Monday revived a peculiar fear in the Russian capital, one that goes beyond the usual terrorism worries of a metropolis: the female bomber.

On Monday, the Russian authorities said that the bombings had been carried out by two women, and that they were searching for two suspected female accomplices, the Russian news media reported. Few details of the bombers were released.

Earlier this decade, Moscow’s fear of female suicide bombers was so strong it became a lurid obsession. Women, sometimes casually clad in jeans and blending in to the swirl of Moscow, committed at least 16 bombings, including two on board planes.

The attacks came early — as when a widow killed herself and the Russian commander who had killed her husband in one of the first such attacks in the Chechen war — and sometimes in the most unlikely places, like mingling in line at a music festival, which only multiplied the horror. Women joined in some of the most well-known terrorist attacks in recent Russian history, at a theater in Moscow and a school in Beslan, Russia.