DHAKA, Bangladesh (AP) _ Opposition activists enforcing a general strike Sunday clashed with police in Bangladesh's capital, leaving at least 20 people injured, witnesses and doctors said.

The daylong street protests across the impoverished country were called by four main opposition parties to demand Prime Minister Sheikh Hasina's resignation.

The opposition, led by former Prime Minister Khaleda Zia, says the government is inept, corrupt and harasses political rivals. The government denies the charges and accuses the opposition of trying to destabilize the administration and the economy.

The strike halted most traffic, shut down businesses and schools in 64 cities and towns, Abdul Mannan Bhuiyan, the opposition spokesman said. Government offices opened, but few people showed up for work.

Sunday is a working day in Bangladesh, a predominantly Muslim nation that observes the Sabbath on Friday.

Several clashes were reported in Dhaka, the capital of 9 million people. More than 5,000 police and paramilitary troops patrolled the streets.

Police fired tear gas to disperse opposition activists after they attacked a state-run bus, witnesses said.

Protesters in Dhaka also exploded crude homemade bombs. At least 20 people were injured in the capital, and three of them were hospitalized, doctors at the state-run Dhaka Medical College hospital said.

The protest came ahead of a meeting of the country's foreign donors, who are scheduled to meet in Paris on April 19-20 to discuss a new annual $2 billion aid package.