BEIRUT — Opposition fighters fired mortars Friday at a corridor set aside for rebels and residents to leave besieged eastern Aleppo, Russian and Syrian officials said, breaking a “humanitarian pause” by Moscow and wounding two Russian soldiers and a Syrian journalist.

For most of the 10-hour halt in fighting, which was unilaterally announced by Russia, no one had approached the corridors, and webcam video from the Russian Defense Ministry showed no activity. There was no U.N. monitoring of the exit routes.

During similar, previous halts in fighting, rebels and civilians in eastern Aleppo also mostly stayed put, saying international monitors were not involved and there were no guarantees of security for those who left. Some battle-hardened residents believe the government would arrest anyone who comes out through the corridors.

About four hours before the pause expired, Syrian state media said seven mortar shells from the rebel-held territory hit one of the corridors in the northern part of the city.

The two Russians were slightly wounded during the shelling, and they were evacuated, but their lives were not in danger, the Russian Defense Ministry said. A correspondent for a pro-government broadcaster also was wounded by shrapnel, Syrian state TV said.

The government of President Bashar Assad largely abided by the halt. Russia, a staunch ally, has been supporting Syria’s fight against the rebels with a campaign of airstrikes as recently as September and October.

The “humanitarian pause” by Russia raised speculation that a major offensive might begin after its expiration at 7 p.m. There were no immediate reports of any new airstrikes there.

U.N. officials in Geneva would not comment directly on the Russian initiative but reiterated that security conditions were not adequate for bringing aid into eastern Aleppo.