The clashes come shortly after the Ukrainian parliament has approved President Petro Poroshenko's proposed constitutional amendments on decentralization in the first reading.

A blast has been heard during the protests near the Verkhovna Rada after several shots had been fired, 112.Ukraine TV channel reported. Local police told RIA Novosti that the reason of the incident is being investigated.

Loud explosion was heard near Verkhovna Rada, a number of policemen are wounded #рада8 pic.twitter.com/bH4Siv1bpY — TV Channel “Ukraine” (@Kanalukraine_en) 31 августа 2015

The Ukrainian Interior Ministry told RIA Novosti that some 100 were wounded in the clashes near the parliament's building. According to Internal Minister Arsen Avakov's adviser Anton Gerashenko, a National Guard soldier died from a shrapnel wound in the heart. The internal minister confirmed the information via his Twitter account.

Deputy Interior Minister Vasily Paskal has been wounded during the clashes, Avakov said at a briefing.

"Deputy Interior Minister [Vasyl] Paskal suffered a shrapnel wound," Avakov said in an interview with 112.Ukraina television.

According to the Ukrainian Internal Ministry's press service, 10 law enforcement officers are in serious condition. The number of injured among the protesters is unknown so far.

According to advisor to the Ukraine's Internal Minister Anton Gerashchenko, a grenade was thrown at law enforcers. The Internal Ministry considers the clashes a terrorist attack, he wrote.

"A grenade was just thrown at servicemen guarding the Verkhovna Rada [parliament]. Several National Guard soldiers have been seriously wounded. Their lives are in danger," Gerashchenko wrote on Facebook.

Провокация у Верховной Рады удались! Только что в военнослужащих охраняющих Верховной Рады была брошена боевая гранат… Posted by Антон Геращенко on Monday, 31 August 2015

Ukrainian Internal Minister Arsen Avakov wrote on his Facebook account that more than 30 were detained over the clashes, including the person who threw a grenade.

"Investigation and punishment are inevitable. Around 30 people are detained. There will be more. The person who threw the grenade has been caught, grenades have been seized, including an F1 maximum destruction grenade," Avakov said.

Dozens of Ukrainian National Guard servicemen were wounded after being hit with a grenade while patrolling outside the parliament.

According to Ukraine's Internal Minister's aide, protesters used grenades and firearms in the attack outside the Verkhovna Rada building in Kiev.

Persons dressed in T-shirts with the logo of far-right Ukrainian Svoboda party were behind the grenade attack, Avakov said via Facebook.

"I believe it is a crime rather than a political statement," Avakov said, adding that a thorough investigation into the riots would be conducted. "This cannot go on… I will not let it happen," the minister stressed.

According to a statement of the Svoboda party, authorities are to blame for the clashes.

"We demand the resignation of Interior Minister of Ukraine Arsen Avakov, whose criminal inaction led to this tragedy," the Svoboda party's statement reads.

According to Internal Minister Avakov, two French correspondents have been injured; they are currently at a local hospital. The OSCE has voiced concern on Monday over the journalists' injuries and called on Kiev to investigate the incident.

Ukrainian President Petro Poroshenko is expected to comment on the clashes in a televised address later on Monday.

About 200 people protested outside the parliament's building calling on Ukrainian lawmakers not to change the Constitution.

UA nation vote:smoke outside the Verkhovna Rada&protesters trying to break through the police border @OksanaDenysova pic.twitter.com/vYStL9L8H2 — Euromaidan PR (@EuromaidanPR) August 31, 2015

A group of protesters outside Ukraine's parliament Verkhovna Rada attempted to storm the building earlier on Monday, a RIA Novosti correspondent reported.

The angry demonstrators were stopped by law enforcers, who used tear gas against the crowd.

Decentralization is one of the key provisions of the Minsk agreements. The deal was signed back in February by representatives of Kiev and Donbass self-proclaimed republics and stipulates several measures on Ukrainian reconciliation.

In keeping with the provisions of the Minsk accords, reached in February 2015, President Poroshenko agreed to grant a special status to the self-proclaimed Donetsk and Lugansk People’s Republics.