A third massive explosion has shaken central Kabul, hours after a Taliban double bombing in the Afghan capital killed at least 24 people and left 91 others wounded.
Sporadic gunfire could be heard late on Monday in an area with many shops and businesses, witness said, and initial reports suggested that a guesthouse had been targeted.
Glass from shattered windows lay on the street near the explosion as police sealed off the area. There was no immediate claims of responsibility and no information on casualties.
Hours earlier, high-level officials, including an army general, were killed in a double suicide bombing close to the Afghan defence ministry in Kabul. The Taliban claimed responsibility for the attack, which occured during the late afternoon rush hour.
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"It [the first blast] happened in the centre of town, just about 4pm (14:30 GMT), a very busy time," said Al Jazeera's Jennifer Glasse, reporting from Kabul.
"The ministry of defense, the ministry of finance, police district two headquarters are all in this area. There are also markets around there."
The first two blasts took place in rapid succession, in an attack apparently aimed at inflicting mass casualties as government staff left the ministry after work.
"When people came to either help the wounded or see what had happened there [after the first blast], the second explosion went off," Glasse said.
Taliban spokesman Zabihullah Mujahid said on Twitter that the defence ministry was the target of the first attack, while police were targeted in the second.
The twin bombings come as Taliban fighters intensify their nationwide offensive against the US-backed government in Kabul.
Mohammad Ismail Kawousi, a spokesman for the public health ministry, said the death toll from the explosions could still rise.
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"The first explosion occurred on a bridge near the defence ministry. When soldiers, policemen and civilians rushed to the scene, there was the second explosion," defence ministry spokesman Mohammad Radmanish told AFP news agency.
Afghan intelligence sources told Al Jazeera that they believed the target of the third explosion on Monday night was a guest house in central Kabul.
"They think some sort of car bomb...went off and several armed assailants have moved in to the area," Al Jazeera's Glasse said.
Our correspondent said Afghan security forces had arrived at the scene.
"They are trying to understand what the target was, and trying to find the gunman in the area," she said.
"We also heard gunfire immediately after the blast."
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President Ashraf Ghani strongly condemned the deadly attacks.
"The enemies of Afghanistan are losing the fight in the ground battle with security forces," Ghani said in a statement.
"That is why they are attacking, highways, cities, mosques, schools and ordinary people."
The latest blasts come more than a week after 16 people were killed when armed fighters stormed the American University of Afghanistan in Kabul, in a nearly 10-hour raid that prompted anguished pleas for help from trapped students.
Explosions and gunfire rocked the campus in that attack, which came just weeks after two university professors - an American and an Australian - were kidnapped at gunpoint near the school.
Their whereabouts are still unknown and no group so far has publicly claimed responsibility for the abductions, the latest in a series of kidnappings in the conflict-torn country.
The increase in violence in the capital comes as the Taliban escalate nationwide attacks, underscoring the worsening security situation since NATO forces ended their combat mission at the end of 2014.
Afghan forces backed by US troops are seeking to head off a potential Taliban takeover of Lashkar Gah, the capital of the southern opium-rich province of Helmand.
The Taliban has also closed in on Kunduz - the northern city they briefly seized last year in their biggest military victory since the 2001 US invasion - leaving Afghan forces stretched on multiple fronts.
NATO coalition forces have insisted that neither Kunduz nor Lashkar Gah are at risk of falling to the Taliban.
Source: Al Jazeera News and agencies