A powerful car bomb struck near Kabul's international airport on Monday evening, just hours after a suicide bomber blew himself up in the war-scarred Afghan capital.
No group immediately claimed responsibility for the blast, which appeared to target a compound for foreign contractors, an Afghan security official told AFP.
Officials said there were no immediate reports of casualties from the explosion, which was strongly felt across downtown Kabul and blew out window panes of homes.
But the Italian-run Emergency Hospital in Kabul said on Twitter: "#Afghanistan two attacks today in , we're currently receiving victims of the at our Surgical Centre".
The violence comes as Afghan forces battle to end a protracted siege near the Indian consulate in the northern city of Mazar-i-Sharif which began on Sunday night.
Gunfights and grenade explosions echoed as commandos battled to flush out militants holed up in a building near the consulate, with powerful provincial Governor Atta Mohammad Noor overseeing the operation.
Nearly 24 hours after the siege began, security officials said they were proceeding cautiously in the residential area to limit civilian casualties.
Earlier Monday, a suicide bomber struck a street leading to the city's international airport, near where the second blast took place, but no casualties were reported.
The bombings mark the latest assaults on the war-scarred Afghan capital.
A Taliban suicide car-bomber struck a French restaurant popular with foreigners in Kabul on Friday, killing two people in a New Year's Day attack.
Fifteen others were wounded in the attack on Le Jardin, an Afghan-owned eatery, which caused a piercingly loud explosion and left a building engulfed in flames.
The spike in violence coincides with a renewed international push to revive peace talks with the resurgent Taliban.
Islamabad is set to host a first round of dialogue between Afghanistan, Pakistan, the US and China on January 11 to lay out a comprehensive roadmap for peace.
Pakistan, which wields considerable influence over the Afghan Taliban, hosted a milestone first round of talks in July but the negotiations stalled when the insurgents belatedly confirmed the death of longtime leader Mullah Omar.