- Police say they arrested 22 people by the time polls closed at 8 p.m.
- A witness reports clashes in Manama and an unconfirmed number of injuries
- The election was for 18 parliamentary seats vacated by opposition party Al-Wefaq
- Protests have lingered in the island nation for months despite a government crackdown
Polls closed Saturday night in a parliamentary election in Bahrain, a day marked by more arrests and clashes between authorities and protesters.
The election was to fill 18 seats vacated by Al-Wefaq, the country's largest opposition party, which pulled out of the Middle Eastern nation's legislature to protest the treatment of demonstrators during unrest earlier this year.
Saturday was marked by more tension. There was no firm count of an injury toll, though many anti-government demonstrators were getting treated for their wounds in makeshift clinics in the capital of Manama, reports an eyewitness, who is not being named by CNN for security reasons.
Around the time the last ballots were cast, at 8 p.m., police said 22 people had been arrested so far. Protests were still ongoing at that time, the witness said.
The tiny island nation has felt the winds of change in the Arab world. Protests have lingered in Bahrain for months despite a crackdown on the Shiite majority nation by the kingdom's Sunni monarchy, backed by troops from Saudi Arabia and the United Arab Emirates.
More than 30 people have been killed in the crackdown, in which activists say Bahraini security forces used live ammunition against protesters. Opposition groups say more than 1,000 people -- mainly Shiites -- have been detained and more than 2,000 have lost their jobs for allegedly taking part in the protests.
In the election, 14 candidates are running unopposed. Authorities will tally votes for the remaining contested seats, the Bahrain News Agency reported. Authorities had stepped up security at polling stations.
Clashes had also been reported Friday in Manama on the eve of the elections. Security forces were sent to rallies to deal with what the Interior Ministry called "illegal acts which resulted from demonstrations," according to the state news agency.
The ministry said saboteurs and outlaws stormed the City Center mall in Manama on Friday afternoon, "intent on sowing chaos and terrorizing shoppers," according to the Bahrain News Agency. Those arrested will face legal action, officials said.
Activists and human rights officials have also cited the stifling of political free expression in schools.
Human Rights Watch issued a report on Saturday urging Bahraini universities to "immediately reinstate all students, faculty, and staff who were dismissed solely for expressing opinions critical of the government and ruling family or attending overwhelmingly peaceful anti-government demonstrations in February and March of this year."
It also urged the University of Bahrain to stop making students sign loyalty oaths of loyalty to the ruling monarchy and government as a condition for enrollment.
That school "dismissed at least 100 faculty and staff between April and August, in most cases for attending anti-government demonstrations or posting links on social media. Hundreds of students have been interrogated and suspended or expelled.
"Bahraini authorities have punished students and professors -- along with thousands of other Bahrainis -- simply for exercising their right to criticize the government," said Joe Stork, deputy Middle East director at Human Rights Watch. "Attacking students and professors who dare to dissent flagrantly violates their right to freedom of opinion and expression."