More than 250,000 people could go without any food after the rations have been delivered.
Moscow blames the West for failing to rein in Islamists in Aleppo.
Aid hasn't arrived, and people are blocked from leaving via designated corridors during ceasefire.
United Nations tries to extend the truce despite continuous ground skirmishes.
Previous ceasefires significantly slowed fighting, though have not yet ended the conflict.
War Child's Colin Walker proposes bold actions the U.K. government could take in Syria.
In interview with Russian site, Syrian leader called city a "springboard" to liberate other areas.
The latest airstrikes are part of a military strategy to empty Aleppo of civilians, writes Amnesty's Diana Semaan.
Putin's spokesman said militants are using the truce to regroup, rearm and attack.
The bombardment comes as the Syrian army prepares a supporting ground assault.
The strike also killed nine rebel fighters in the town of Khan Touman, NGO and monitors said.
Dozens of strikes in or around Aleppo left at least 32 people dead after the ceasefire ended.
The "regime of calm" came to an end at midnight on Monday.
Truce brokered by U.S., Russia goes into effect Monday after five years of civil war.
Syrian army attacks rebel-held areas in Aleppo hours after ceasefire deal is announced.
Two powers were close to a deal but ceasefire terms are still to be worked out.