* Khawaja refused to make videotaped apology to king
* Nine policemen run over by protester - state TV
* Khawaja one of 21 charged with trying to topple govt
(Adds pro-government demonstration, court rulings)
By Jason Benham
DUBAI, May 17 (Reuters) - A prominent Bahraini human rights activist said he had been threatened with rape while in custody after he refused to apologise to the king over his role in anti-government protests.
During a demonstration on Tuesday, a protester drove his car into a group of policemen and injured nine of them, state television reported.
Human rights groups said Abdulhadi al-Khawaja, former president of the Bahrain Centre for Human Rights (BCHR), was removed from a military court on Monday on the third day of his trial after he told the judge about his treatment.
He said that despite prior complaints the court had not taken action to secure his safety.
"The judge refused to listen to these statements and Mr Alkhawaja was ordered out of the courtroom," BHCR and Bahrain Youth Society for Human Rights said in a joint statement.
The interior ministry media office said no one was available to comment on the report. Other officials could not be reached.
Khawaja is one of 21 activists charged with trying to topple the Sunni-led government during weeks of popular Shi'ite protests, calling for greater political freedoms, an end to sectarian discrimination and a constitutional monarchy.
Some hardline Shi'ite groups also called for a republic.
Khawaja has in all three trial sessions so far voiced allegations of abuse but was silenced by the judge on each occasion, the two rights groups said in their statement.
The rights groups said Khawaja told relatives and his lawyer that he had been taken by four men to an unknown location where a man there told him he was a representative of the king.
They asked him if he would apologise in a video message and he refused, then he was taken to a room where the men used "foul language and threatened him with rape", the rights groups said, adding they also threatened to rape his activist daughter.
"At this point the men started undressing and showing their private parts after which they started touching (Khawaja) inappropriately," the rights groups reported.
"When they tried to take off his pants, he threw himself down and started hitting his head on the ground continuously until he almost passed out. Seeing this they returned him to his prison cell."
NINE POLICE HURT, FOUR SERIOUSLY
Bahrain's TV said four policemen were seriously wounded during renewed unrest on Tuesday.
"As security men carried out their duty ... and confronted a group attempting acts of tumult and sabotage, one of those involved was injured in the head, and his brother immediately started driving at full speed and running over officers," the channel quoted a police official as saying.
It carried footage of a police vehicle and a saloon car, both damaged, and showed injured men being treated at a hospital.
About 1,000 pro-government demonstrators later gathered to condemn the attack on the police and demand tougher measures by authorities to guarantee security, a resident said.
Human Rights Watch said last week Khawaja bore visible signs of ill-treatment and perhaps torture and called on Bahrain to set up an impartial body to look into allegations of torture.
A Western lawyer and an observer from an international rights group were banned from attending the trial on Thursday.
In further sign of a tough stance against protesters, a military court sentenced eight demonstrators, including an Iranian man, to up to four years in jail on charges including staging illegal rallies, rioting and possessing anti-government leaflets, state media reported on Tuesday.
Seven men were jailed for up to three years on similar charges on Monday.
Hundreds of people, mainly Shi'ites, have been arrested and dozens put on trial. Others have been fired from government jobs. A state of emergency is due to be lifted on June 1.
Bahrain has also forced university students to sign a pledge "not to organise or participate in any events and activities that would harm the reputation of Bahrain domestically and internationally," a document, seen by Reuters, showed.
The government document said students who did not sign the pledge were demonstrating that they did not want to continue their education at the University of Bahrain.
At least 29 people, all but six of them Shi'ites, have been killed since the protests started in February, inspired by Arab revolts that ousted the autocratic rulers of Egypt and Tunisia.
The six non-Shi'ites included two foreigners -- an Indian and a Bangladeshi -- and four policemen. (For a WITNESS story on Bahrain, please click on [ID:nLDE74A0E1]) (Reporting by Jason Benham; Editing by Cynthia Johnston and Samia Nakhoul)