Sri Lanka's main opposition on Saturday warned of an uprising, a day after ruling party activists unleashed violent attacks against demonstrators seeking the release of a jailed opposition leader.
The United National Party (UNP) said repeated violence against the opposition, arson attacks on anti-government news organisations and arrests of student leaders could lead to protests similar to those sweeping the Arab world.
"The rulers cannot suppress the people forever," UNP deputy leader Karu Jayasuriya said in a statement. "We urge the government to look at what is happening in the Arab world and learn a lesson."
Violence erupted in the capital on Friday night when ruling party activists attacked a UNP-led march demanding the release of their presidential candidate and former army chief Sarath Fonseka, who is serving a 30-month prison term.
At least four opposition MPs were among a dozen people wounded in the Friday night attack, while cars belonging to opposition lawmakers were smashed by ruling party activists.
"The two groups fought as the protest march went past a religious ceremony organised by some government lawmakers," police deputy inspector general Anura Senanayake said on Friday night.
There was no immediate comment from the government.
Mass protests gripped Sri Lanka soon after Fonseka's arrest last year, but opposition rallies since then have seen diminished crowds.
Fonseka is widely credited with leading troops to crush Tamil Tiger rebels and ending the island's 37-year separatist war in May 2009. However, he fell out with President Mahinda Rajapakse on sharing the credit.
Fonseka was arrested two weeks after failing to unseat Rajapakse in the January 2010 presidential ballot. A court martial later found him guilty of irregularities when he was army chief.
The opposition has said it will stage a mass rally in Colombo next week to mark the first year since Fonseka's arrest by the military.
Fonseka's imprisonment has meant the loss of the seat he won in parliament last April and the right to stand for public office until 2017.