Schools and businesses were shut in Bangladesh's capital on Sunday as opposition parties enforced a daylong general strike across the South Asian nation.

An 18-party opposition alliance was enforcing the strike to urge the government to find a regional opposition leader who went missing on Tuesday.

Security officials cordoned off the headquarters of the main opposition Bangladesh Nationalist Party, but the first few hours of Sunday's strike were largely peaceful.

Traffic on the usually clogged streets of the capital, Dhaka, was thin amid tight security, with several thousand police deployed across the city of 10 million people.

Sunday is a working day in Muslim-majority Bangladesh.

On Saturday, arsonists set fire to buses in Dhaka ahead of the strike, killing one man, police and media reports said.

Police official Sirajul Islam said a parked bus was set on fire Saturday in Dhaka's Khilgaon area, killing the 40-year-old driver, who had been asleep inside.

It was not clear who was behind the arson.

The United News of Bangladesh agency and several television stations said several other buses were set on fire Saturday in parts of Dhaka.

The opposition has blamed security agencies for the disappearance of the regional leader, Elias Ali, but the government has denied this, accusing the opposition of hiding him in order to create anarchy in the country.

Ali's wife said in a police complaint that her husband left their home in Dhaka late Tuesday and that he and his driver have been missing since.

His car was found by residents on a Dhaka street early Wednesday, abandoned and with its doors open.

Ali's disappearance has further complicated Bangladesh's politics. Former Prime Minister Khaleda Zia's Bangladesh Nationalist Party has been holding anti-government protests for months to demand an independent caretaker government oversee elections. The government of Prime Minister Sheikh Hasina scrapped the 15-year-old system last year, saying it contradicted the constitution.

The opposition says elections will be rigged if held under the current government.

General strikes are commonly used by the opposition in Bangladesh to embarrass the government.