VIDEO: Moment masked, hooded men unleashed teargas during Ol Kalou by-election

Armed, hooded and masked men sparked panic after unleashing tear gas on Ol Kalou residents as the sleepy town headed to the polls.

The incident briefly threw the parliamentary by-election into chaos after voting had started peacefully.

The masked men were captured on video hurriedly alighting from a convoy of black, nearly uniform SUVs.

In one clip seen by TNX Africa, a fully masked individual stepped out of a vehicle, went quickly back in and fired what appeared to be a teargas canister into the air.

Moments later, a black Toyota Land Cruiser Prado sped off as the rest of the convoy followed. In another SUV, a man was seen standing through the sunroof while holding a rifle aloft.

The scenes triggered panic among voters who had turned up to cast their ballots.

Less than an hour later, more videos surfaced showing angry residents confronting and turning back the convoy carrying the armed, hooded men.

During the standoff at AC Primary School, the armed men also targeted journalists.

An NTV cameraman was allegedly tasered, assaulted and had his camera confiscated, while a Nation reporter was threatened at gunpoint and had her mobile phone forcibly taken.

Nation Media Group Board Chairman Joe Muganda strongly condemned the attack, describing it as a direct assault on press freedom and the public's right to information.

"The assault on our journalists is an attack not only on members of our staff but also on the principles of press freedom and the public's right to receive timely and accurate information. An attack on journalists is an assault on the public's right to know," Muganda said.

Civil society groups and political stakeholders also condemned the violence and the intimidation of election observers and journalists.

"Reports of excessive use of force by security agencies, violence around polling areas, and the harassment of duly accredited journalists carrying out their lawful duties are unacceptable. The media plays an indispensable role in safeguarding electoral transparency and public accountability," the Centre for Multiparty Democracy said in a statement.