Police and protesters have clashed in several parts of Bangladesh as demonstrators took part in an anti-government strike.

Thousands of security personnel were deployed across the country Wednesday. In a scuffle with opposition lawmakers in the capital, Dhaka, an official from the main opposition Bangladesh Nationalist Party suffered a head injury during.

Home Minister Sahara Khatun has warned the government would do whatever is necessary to maintain order.

Authorities said police also arrested at least seven people Wednesday, as opposition parties took to the streets to demonstrate against a government they accuse of clinging to power and undermining democracy.

The strike forced businesses to close and disrupted the country's main port in the city of Chittagong.

The BNP and its allies, including the Islamist group Jamaat-e-Islami, began the strike to protest last month's parliamentary approval of a constitutional amendment that scraps a system of holding national elections under a non-partisan caretaker government.

Lawmakers from the ruling Awami League of Prime Minister Sheikh Hasina passed the amendment in a June 30 vote boycotted by the BNP.

Opposition members accuse Ms. Hasina of amending the constitution to keep her party in power through fraud, rather than allowing non-partisan technocrats to oversee Bangladesh's next elections.

The country's supreme court has ruled the system of installing 90-day interim administrators to supervise elections is unconstitutional.