An Afghan security guard at the German embassy was killed and several of its employees injured in the explosion, which was caused by a device in a tanker truck in Kabul's diplomatic district.
Large parts of the German embassy were damaged in the blast, killing at least 80 people and injuring 350 others, a Public Health Ministry spokesman said.
Little is left of the vehicle - either a water or human waste tanker - that was used for the bombing, said Najib Danish, a spokesman for the Afghan Interior Ministry.
In the past, the majority of Afghans whose asylum bids were declined were allowed to remain in Germany due to the security threat in their country. But Berlin decided last year to designate parts of Afghanistan safe for return.
The deportations have come under fire in Germany from opposition parties and rights groups who argue that much of Afghanistan is not safe for return.
The government source said Wednesday that nothing had changed regarding the government's fundamental stance on deportations to Afghanistan, but that embassy staff had "more important things to do" than receive failed asylum seekers in the coming days.
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