At least 14 foreign security guards have been killed when a suicide bomber attacked a minibus in Afghanistan's capital, Kabul, police said.

The attacker on Monday was on foot, police said, as they reported multiple casualties among the bus passengers who were "employees of a foreign compound".

The Taliban took responsibility for the attack, a spokesman for the group confirmed to Al Jazeera.

Less than three hours later, another attack in eastern Kabul apparently targeted an MP and injured four civilians.

Al Jazeera's Qais Azimy, reporting from Kabul, said after the first attack that "Afghan police told us they have reports that this kind of attack could happen again".

The bus was carrying Nepalese guards, according to a witness, who also reported more than two dozen ambulances at the scene.

It is the first attack in Kabul since the start of holy fasting month of Ramadan on June 6.

"Kabul had been quite peaceful during the first two weeks of Ramadan," said our correspondent.

"But this is not the first such attack. Most of the time, the target they [the Taliban] take shows they have good intelligence and capability," he added. "They want to show they can attack any target they want."

The last attack in the Afghan capital on April 19 left 64 dead and more than 340 wounded.

That attack was claimed by the Taliban, which has fought the Western-backed Kabul government since the group were ousted from power by a US-led invasion in late 2001.