Manama (AsiaNews/ Agencies) - Police used tear gas and stun grenades against hundreds of demonstrators who took to the streets of Shiite villages in Bahrain on May Day to demand their reinstatement in the jobs from which they were fired during last year's Arab spring uprising. Dozens of demonstrators were arrested. The rallies were organised by the 14 February youth movement.

According to the Bahrain Labour Union, almost 600 workers were fired from private and public sector jobs for taking part in the uprising.

Meanwhile, human rights activist Abdulhadi al-Khawaja continues his hunger strike. He was arrested almost a year ago and has been kept in isolation ever since.

According to Human Rights Watch, the authorities have not yet provided any evidence that he was involved in subverting the state or linked to terrorist groups.

Yesterday, al-Khawaja said that he would pursue his hunger strike until the government releases all the people it has arrested.

For its part, the government announced plans to put on trial 20 medics on charges of incitement to overthrow the government and trying to occupy a hospital. Rights groups said that the 20 were arrested for treating protesters wounded by security forces last year.

The majority of the people of Bahrain are Shia, but the country is ruled by a Sunni royal family, an ally of Saudi Arabia.

For more than a year, people have demanded constitutional reforms and the removal of Prime Minister Sheikh Khalifah ibn Salman al-Khalifah, who has been in office since 1971.

In March 2011, the Shia opposition organised a popular revolt in the wake of the Arab spring.

In order to end the demonstrations, the government called on its Saudi ally for help. Saudi Special Forces were sent in with the power to use lethal force against demonstrators. Twenty-four people, including four police officers were killed.

Unrest began again on 18 April of this year during the Formula 1 Grand Prix. For days, thousands of demonstrators took over the streets of the capital and in predominantly Shia villages.

The authorities responded by imposing a curfew and arresting hundreds of people.