Afghan officials say the death toll from twin bombings near the parliament building in the capital, Kabul, has risen to 38, with civilians and military personnel among the victims.
More than 70 others were wounded in the attack, claimed by the Taliban.
The January 10 attack in Kabul came just hours ahead of a powerful blast in a government guesthouse in the southern province of Kandahar that killed at least five people and injured some 14 others, including the provincial governor and the Emirati ambassador to Afghanistan.
In Kabul, the initial blast struck about 4 p.m. as employees were leaving a compound of government and legislative offices, said Interior Ministry spokesman Sadiq Sadiqi.
Sadiqi told RFE/RL's Radio Free Afghanistan that a suicide bomber blew himself up, followed by a car bomb in the same area in "what appears to have been a coordinated attack."
The second explosion occurred after security forces had arrived at the scene.
According to some reports, another vehicle with explosives was stopped by security forces near the area.
A Taliban spokesman said the attack targeted a minibus purportedly carrying Afghan intelligence agency staff, but that claim could not be confirmed.
The Interior Ministry said at least four police officers were killed in the attack.
Afghan media reported that a district head of the National Directorate of Security, Afghanistan's main intelligence agency, was among those killed.
Media reports say most of the victims were civilians, including parliament staff. Rahima Jami, a female lawmaker from the western Herat Province, was among the wounded, the Tolo news agency reported.
The wounded were taken to Istiqlal and emergency hospitals.The head of Istaqilal Hospital, near the scene of the bombings, told RFE/RL that more than 60 people have been brought to the hospital for treatment.
Amnesty International condemned the attack, saying it "indicates that the Taliban are pressing ahead with a gruesome campaign of violence that makes no effort to spare civilian lives."
The rights watchdog called for an independent investigation to "secure justice for the victims and their families."
Meanwhile, there was no immediate claim of responsibility for the Kandahar guesthouse attack that occurred at 7 p.m. local time.
Local government spokesman Samim Khpalwak said the blast hit the compound in the provincial capital, Kandahar, where Governor Hamayoon Azizi was hosting a dinner attended by the ambassador of the United Arab Emirates to Kabul as well as several Afghan officials and Emirati diplomats.
The governor and the ambassador were among the wounded, Khpalwak said.
The U.A.E. foreign ministry confirmed the incident, saying in a statement that Ambassador Juma Mohammed Abdullah al-Kaabi and several other Emirati diplomats were injured in "the heinous terrorist attack on the guesthouse." It didn’t disclose the number of the U.A.E. diplomats wounded in the attack.
The diplomats were attending charity events in Kandahar.
U.A.E. combat troops were deployed to Afghanistan after the 2001 U.S.-led invasion that toppled the Taliban administration.
Also on January 10, at least seven people were killed and six injured by a suicide-bomb attack Helmand province in the south of the country, the provincial chief of police said.
The attack reportedly occurred in the house of a local tribal elder.
There was no immediate claim of responsibility for the Helmand attack, but it bore the hallmarks of the Taliban.
With reporting by AP, dpa, AFP, Reuters, and the BBC