Two of the soldiers received minor injuries from the attack and the third was hospitalized.
Intelligence figures in Britain suggested that the attack was not against the royal family but instead against the unarmed police guarding the outside of the building.
Upon being challenged by officers, the man reached for what police described as a four-foot sword which was in the front passenger foot well.
In June, authorities foiled a suspected terror attack on the Brussels central station, where a man was shot, after causing a small explosion, reports the Guardian. Jambon said that the Belgian national has committed some "acts of vandalism " in the past but was not known or preparing acts of terrorism, extremism or radicalism.
Queen Elizabeth was not in residence in the palace when the attack outside the palace happened.
Hours later, a similar incident occurred outside of Buckingham Palace in London, England.
The man was described by Belgian prosecutors as a 30-year-old "not known for terrorist activities".
One soldier was "slightly injured", she added.More news: Wenger and Arsenal confident over contract rebels
"Following the incident in the center of Brussels on the evening of Friday, 25 August 2017, a coordination meeting was held at the Crisis Center".
Following close on the heels of the Barcelona attack, the incident is being treated as a terror attack, said Belgium's federal prosecutor's office.
Soldiers and police have repeatedly been targeted by lone extremists in France, Belgium and Germany, using weapons including knives, machetes, a hammer and a auto filled with homemade explosives. The man was also carrying a fake firearm and two copies of the Quran, the Muslim holy book.
The assailant was a Belgian national of Somali origin who was born in 1987, authorities confirmed. Migration Minister Theo Francken said the man had been granted asylum in 2009 and gained Belgian citizenship in 2015.
While he had no previous connection with terror before Friday night's attack, he did have an assault charge on his record from February this year, a statement said.
The armed accused had allegedly shouted "Allahu Akbar" while running towards the soldiers patrolling near a pedestrian zone in the capital city. Witnesses said he yelled "Allahu Akbar" just prior to the attack.
One soldier then opened fire.
Brussels was the location of the first Isis-linked attack in Europe, where a militant killed four people at the Jewish Museum of Belgium in May 2014.