Hours after the blast, a health ministry spokesman said the casualty toll had risen to at least 95 killed and 158 wounded.
Matiullah Wesa, an education activist in Afghanistan, wrote: "This is our life in #Afghanistan everyday looking for loved ones to be safe from danger". Pakistan says the Taliban cross the porous border that separates the countries along with the estimated 1.5 million Afghan refugees still living in Pakistan.
Nicholson said the terrorists care nothing for the people of Afghanistan.
He commended all the emergency services personnel for their courageous actions in responding to this terrorist attack.
Afghanistan is witnessing one of its bloodiest periods, following the end of NATO's military mission although it continues its presence in the country for training Afghan forces. "Unarmed civilians throughout Afghanistan regularly bear the brunt of this cruelty", he said.
In the clashes, five soldiers were also killed.
The attack in one of the most heavily protected parts of the city was the worst in the Afghan capital since a truck bomb killed 150 people in May.
The government declared a day of mourning, with shops closed and flags at half-staff.
The blast - one of the biggest since a truck bomb ripped through the Afghan capital's diplomatic quarter on May 31 past year - led to chaotic scenes as panic-stricken people fled the area where several high-profile organisations, including the European Union, have offices.