Bangladesh was on high alert ahead of a verdict Thursday against opposition leader and former Prime Minister Khaleda Zia in a politically sensitive corruption case.

The case involves an orphanage trust established during Zia's last premiership in 2001-2006. The charges allege Zia, her elder son Tarique Rahman and four others were involved in embezzling $248,154 from the trust. If found guilty, they face a maximum punishment of life in prison.

Thousands of police and other security forces were patrolling the main cities and towns. In the capital Dhaka alone, about 10,000 police and paramilitary border force were out on the streets manning checkpoints. Traffic was light on usually clogged roads.

As Zia began her journey toward the court in Dhaka's old city from her residence in Gulshan diplomatic zone, thousands of her supporters poured onto the streets and surrounded her motorcade. They chanted anti-government slogans and moved on by cordoning off the motorcade as it slowly progressed.

Local TV stations broadcast the movement of Zia's motorcade live amid fear of violence. Thousands of supporters of the ruling Awami League party also took to the streets to show their support to Prime Minister Sheikh Hasina, Zia's archrival.

The opposition has accused the government of arresting hundreds of supporters ahead of the verdict.

The leading Bengali-language daily Prothom Alo reported Thursday that some 1,200 leaders and activists have been arrested since Wednesday. Authorities have warned of tougher measures against any attempts of violence.

The verdict is politically sensitive because if convicted, Zia will be barred from contesting elections slated for December, which would seriously undermine her Bangladesh Nationalist Party.

Zia's son, Rahman, a senior party leader and an heir-apparent in the country's dynastic politics, lives in London as he also faces several other cases. He is being tried in absentia along with two others. Two defendants are behind bars.

Zia faces more than 30 other cases on charges ranging from corruption to sedition.

Bangladesh is a parliamentary democracy but its politics is deeply fractious with Hasina and Zia having ruled the country alternately since 1991, when democracy was restored.

In the last election in 2014, Zia's party and other partners boycotted the race, making way for Hasina to return to power with a landslide victory.