Kenya’s president William Ruto has declared a state of emergency after protests against a new tax bill turned violent as demonstrators stormed the parliament and set fire to the building on June 25.

Ruto called the attack on parliament a “national security threat” and vowed that such unrest won’t happen again “at whatever cost,” AP reports.

Hundreds of anti-tax protesters stormed Kenya’s Parliament in the capital Nairobi and set part of the building on fire. Five protesters have reportedly been killed after police started firing at the crowds, according to human rights organisations, including Amnesty International and the Kenya Medical Association.

Kenya’s defence minister said the military has been deployed to support police during the mounting “security emergency.”

The Kenya Human Rights Commission shared a video of officers shooting at protesters, and it urged Ruto to issue an immediate order to “stop the killings,” ABC News reports.

Demonstrators are demanding the finance bill be nixed, to prevent it imposing new taxes on citizens. Tension has been building as a result of the rising cost-of-living and soaring prices for fuel, food and other necessities in east Africa’s economic hub.

After the bill was passed, lawmakers fled through a tunnel under the parliament building, narrowly escaping the protesters, who stormed the building and started fires.

Protests and clashes with the police have taken place in several other cities and towns across the country, Al Jazeera reports. Protesters a;so tried to storm the State House in the western city of Nakuru, AP reports and there were clashes in the western lakeside city of Kisumu. The governor of Mombasa, Kenya’s second largest city, joined protesters outside his office and expressed his support for them, according to reports. Protesters burned ruling party offices in Embu in central Kenya, the Nation newspaper reported.

Tensions escalated earlier in the day after parliament approved the tax reform finance bill despite growing street protests against the bill.

Ruto said in his first comments on the escalating violence that “criminals” hijacked the demonstrations, and the protests are threatening the sovereignty of the nation.

Kenyan police fired live ammunition into a swelling crowd earlier in the day, injuring dozens, as protests against controversial tax reforms began to spin out of control.

Police were out in force and using tear gas in an attempt to maintain order.

Amnesty International said in a statement that many protestors have already been wounded in the violence.

The Kenya Medical Association said that at least 30 protestors have been wounded, of which 13 were suffering from bullet wounds.

An Al Jazeera correspondent reports the centre of Nairobi has descended into chaos. A Reuters correspondent reported seeing at least five dead bodies. A paramedic, Vivian Achista, told Reuters that at least 10 had been shot dead. Another paramedic, Richard Ngumo, said more than 50 people had been wounded.

Ruto is outside Nairobi attending an African Union retreat.