So far, Mr. Modi appears to be projecting toughness while trying to avoid a deeper conflict. Photos in Indian media showed military convoys on the winding roads approaching the disputed region, and local residents described heavier than usual troop movement. Even so, military analysts said that forces had not been put on full alert.

Mr. Modi, who met with his defense and foreign ministers Tuesday night at his home, already faced criticism from opposition leaders that he was feckless, despite his nationalist appeals and his sharp response last year to an attack linked to a militant group based in Pakistan.

“Why is he hiding?” Rahul Gandhi, one of India’s most prominent opposition leaders, wrote on Twitter. “Enough is enough. We need to know what has happened. How dare China kill our soldiers? How dare they take our land?”

Mr. Modi’s media allies could help him weather the storm. On Wednesday, media friendly to his party circulated unsubstantiated reports that Indian troops had won the skirmish. If people believe the reports, true or not, that could lessen the pressure to retaliate.