Lome, Togo (CNN) -- Togolese security forces shot canisters of tear gas to disperse angry anti-government protesters who demonstrated against a new electoral law Tuesday in this capital city.
Protesters defied the security forces for three hours, throwing stones and other objects.
The West African nation's parliament passed the law two weeks ago, ahead of parliamentary and municipal elections due in October.
"This law is unfair," shouted one supporter of the Save Togo Movement, which is composed of six opposition parties and nine civil society organizations. "It favors the ruling party, and we are not going to tolerate that this time around. We are going to fight every day until it's withdrawn from parliament."
As the clashes continued in opposition strongholds of this port city in southern Togo, militants set tires ablaze along some of the streets in the capital while security forces engaged them in street battles.
"This motley gathering is a lever exploited by certain members of the opposition prior to the legislative elections with the goal of creating an artificial tension," the posting said.
Security forces said the intervention was necessary.
"We were compelled to shoot tear gas to disperse them because they began hurting our forces with stones and we were not ready to take that long," said Col. Yark Damehame, commander of the National Gendarmerie in charge of the security forces.
Zeus Ajavon, a lawyer who helped organize the demonstration, blamed the clashes on security forces, saying they sparked the violence by arresting some of the militants.
"We want these three-day demonstrations to have an impact and we want the law to be purely and simply withdrawn from parliament," he said.
Ajavon said the electoral law "amounts to the ruling party's attempt to rig the next elections" and promised not to give up if his goals are not immediately achieved. "If the government doesn't react at the end of the three-day demonstrations, we will call on new demonstrations in the coming days," he vowed.
A number of shops in Lome's commercial center remained closed after the demonstrations.