Police said two people had died in Monday's incident but did not give their identities, while the attacker was shot dead by armed guards as he approached the gate, in one of the first such attacks since the Taliban took power last year.
"The suicide attacker before reaching the target, was recognised and shot by Russian embassy (Taliban) guards ... there is no information about casualties yet," Mawlawi Sabir, the head of the police district where the attack took place, told Reuters.
The Russian Foreign Ministry said in a statement that an unknown militant set off an explosive device near the entrance to the consular section of the embassy around at 10.50am local time on Monday.
"As a result of the attack, two employees of the diplomatic mission were killed, and there are also victims among Afghan citizens," the ministry said.
Russia is one of the few countries to have maintained an embassy in Kabul after the Taliban took over the country more than a year ago. Although Moscow does not officially recognise the Taliban's government, they have been in talks with officials over an agreement to supply petrol and other commodities.
The United Nations' mission in Afghanistan (UNAMA) condemned the blast.
"In light of recent events, UNAMA stresses the need for the de facto authorities to take steps to ensure the safety and security of the people as well as diplomatic missions," the UN wrote on Twitter, in reference to the Taliban government.
During the decades-long Taliban insurgency against the western-backed Afghan government, bombings targeting foreign missions were a regular occurrence in Kabul, especially in recent years, with embassies and hotels fortifying themselves with razor wire and blast walls.
Such incidents have decreased dramatically since the insurgent group swept to power in August 2021.
Since then, attacks - some of them claimed by Islamic State - mainly targeted the Taliban and civilian targets such as mosques.
No group has claimed responsibility for Monday's blast.
