LOME, April 21 (Xinhua) -- At least four were injured on Wednesday in clashes between opposition protesters and security forces, a government statement said.

The government was launching a probe to interrogate the perpetrators and would "bring them to justice," the statement said, adding that the opposition demonstration was "illegal."

Hundreds of supporters of opposition candidate Jean-Pierre Fabre gathered on Wednesday for a pray and then marched on the street to protest the re-election of incumbent President Faure Gnassingbe.

The protesters set tyres into fire, erected road blockades and threw stones at the security forces when the troops used tear gas to disperse them.

Fabre protested the March 4 election results, which put Gnassingbe in the lead with 60.88 percent of the total votes. Fabre got 33.93 percent of the votes.

Six candidates including a woman ran against Gnassingbe. Gnassingbe came to power in April 2005 after the fiercely contested election that was organized following the death of his father, General Gnassingbe Eyadema, who was in power for 38 years.