KABUL, Afghanistan -- At least six people were killed and 87 others were wounded when several explosions erupted on Saturday during a burial ceremony held in northern Kabul, CBS News producer Ahmad Mukhtar reports.

Wahid Majroh, a spokesman with the Ministry of Public Health, says the death toll is likely to rise.

Authorities say government officials, including members of parliament, were attending the funeral when three explosions blasted the area.

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The ceremony was held for Sen. Alam Ezadyar's son, Salim, who was killed in Friday's violent clashes between Afghan police and protesters, who were calling for more security and the resignation of Afghan President Ashraf Ghani's government. More than 1,000 people demonstrated in the protest.

Ezadyar is deputy speaker for the upper house of the country's parliament.

According to Mukhtar, Chief Executive Abdullah Abdullah, who survived the blasts, did not sustain injuries in the attack. Abdullah appeared on local TV and said the trio of suicide bombers detonated their vests just as mourners were beginning to offer their prayers.

Abdullah called for an investigation into the funeral attack to determine how the bombers entered the ceremony. He also said those responsible for Friday's killings will be investigated and prosecuted.

Friday's protest was held in the capital following a massive truck bomb attack Wednesday that claimed the lives of 90 people and wounded more than 450.

Most of the casualties from the truck bombing were civilians, including women and children. But the dead also included Afghan security guards at the facilities, including the U.S. Embassy. Eleven American contractors sustained non-life threatening injuries.

The attack raised fears about the government's ability to protect its citizens nearly 16 years into a war with insurgents.

No one has claimed responsibility for the attack, which came in the first week of the Muslim holy month of Ramadan.