Image copyright AP Image caption Attempts to restore power have failed and the cause of the problem remains unclear

Bangladesh has been hit by major blackouts after a power line connecting the country to India's electricity grid failed, reports say.

The blackout began at about noon local time and affected all parts of the country linked to the national grid.

Within a few hours some power plants began operating again but they have since failed. It is not clear when supply might resume.

Bangladesh began importing electricity from India in October last year.

Officials said engineers were working to restore supply. They had hoped to fix the problem by Saturday evening.

The exact cause remains unknown, but the head of the national grid in Bangladesh, Chowdhury Alamgir Hossain, told the Dhaka Tribune newspaper that the power cut began after a technical glitch at a substation distributing power from India.

That had caused all the country's other power plants to close down one by one, he said.

The high-voltage transmission line runs from Baharampur in West Bengal, India to Bheramara in Kushtia district, in south-west Bangladesh.