In the first incident, a Taliban suicide car bomber targeting a NATO vehicle rocked the southeast of the city, wounding three people including one described by the police as a "foreigner".
An hour later three Taliban attackers tried to storm a branch office of the National Directorate of Security (NDS), Afghanistan's main intelligence agency.
One militant on a motorcycle blew himself up, killing a guard, before other guards killed his two colleagues.
NATO ended its combat mission in the war-torn country in December, maintaining a smaller residual force for training but leaving Afghan troops and police to face their first "fighting season" battling the Taliban on their own.
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In the wake of the car bomb the street was strewn with rubble and broken glass after the blast, which left a white SUV badly damaged and on fire.
"We can confirm an attack on coalition forces occurred in Kabul at approximately 11:30am," a spokesperson for the coalition told AFP adding that no foreign forces were killed in the attack.
The second attack, on the spy agency, occurred in the same area of the city.
"One attacker on a motocycle detonated his explosives at the gate of an NDS office, killing a guard and wounding two," said Abdul Rahman Rahimi Kabul police chief.
The toll was confirmed by the NDS in a statement.
Today's violence comes a week after a Taliban suicide car bomber targeted a NATO military convoy on the main road to Kabul airport, killing at least two Afghan civilians and wounding around 17.
A week before that, insurgents launched a brazen attack on the Afghan parliament. Police and soldiers beat back the attack with only two civilians killed,.