A Bahraini court has jailed opposition activist Zainab al-Khawaja for one month.

Al-Khawaja was convicted of attacking a  policewoman and taking part in an illegal rally on, witnesses said.

Zainab had been charged with "using force against a policewoman and insulting her as forces of order tried to disperse an  unauthorised rally" on April 21.

Khawaja, who has been active in holding anti-government protests since last year's uprising, was accused of obstructing  traffic on the same day by sitting in the middle of the main King Faisal Road in Manama, the Bahraini capital.

Zainab is the daughter of prominent jailed activist Abdulhadi al-Khawaja, who has  been on hunger strike since February 8.