Police also searched a village house in a northern neighbourhood where they found laboratory equipment they suspect could be used for producing explosives. The arrested men were aged 21-29, a senior officer said late on Tuesday.
Around 900,000 people have been forced from their homes and shelters in less than three months, leaving huge numbers to sleep rough in the thick of winter.
The roadside bombs were spaced within 10-20 metres of one another, said Kabul police spokesman Ferdaws Faramarz. The wounded child is a 12-year-old girl, he said, and added that the police are searching the area where the bombs struck.
Sunday evening's attack took place at a military centre where at least 150 members of the Afghan army and intelligence wing were stationed, according to government officials and the Taliban.
Amsterdam police said in a statement that they are taking into account the possibility that the letters are linked to a string of letter bombs and warning letters sent to businesses last month.
The bomb was found by a fisherman on Elizabeth Reef near Lord Howe Island, about 550 kilometres (340 miles) off New South Wales state. He photographed his discovery and reported it to authorities.
The British bomb that weighed 500-kilogramme was found on a construction site on Thursday, said the emergency services.
The Taliban claimed responsibility for the blast in the northern province of Balkh, saying on Twitter they had attacked the commandos. The defence ministry said two members of the commando force were killed and six wounded, while the rest of the casualties were civilians.
The bus was taking the doctors, nurses and other health workers from Kabul toward northern Panjsher province when it was attacked in the northern district of Kalakan in Kabul province, he added.