May 31 (UPI) -- A car bomb exploded during morning rush hour Wednesday in Kabul's diplomatic district, killing at least 80 people and injuring more than 300 others, Afghanistan's health ministry said.
The number of casualties was expected to rise.
Police said the blast, described as "one of the biggest" to hit the Afghan capital, occurred in Zanbaq Square, close to many government offices and foreign embassies.
"The explosion was so loud that it shattered all my windows," Kabul resident Fatima Faizi told Al Jazeera. "Did not hear something this big before."
The suicide attack may have targeted the German Embassy, authorities said.
"It was a car bomb near the German Embassy, but there are several other important compounds and offices near there too," said Kabul police spokesman Basir Mujahid. "It is hard to say what the exact target is."
The blast broke windows and damaged ceilings of the Korean Embassy and employee residence, a foreign ministry official told The Korea Times, which reported that all embassy staff members were safe.
No group had claimed responsibility for the attack, which police said came from a water tanker truck packed with explosives. Both the Taliban and Islamic State have staged large-scale attacks in Kabul.
Last month, the Taliban announced a "spring offensive" in Afghanistan targeting foreign troops.
In April, a Taliban attack on an Afghan army base killed at least 140 soldiers.
Earlier this month, eight people were killed in a suicide bomb attack on a NATO convoy.