DHAKA, Bangladesh (AP) — Authorities in Bangladesh detained a key opposition figure of the Bangladesh Nationalist Party which called for a nationwide strike Sunday.

This comes a day after clashes — which left at least one policeman dead and scores injured — erupted during a massive rally demanding the resignation of Prime Minister Sheikh Hasina and the transfer of power to a non-partisan caretaker government to oversee general elections next year.

Faruk Hossain, a deputy commissioner of Dhaka Metropolitan Police’s Media Cell, told The Associated Press that Mirza Fakhrul Islam Alamgi was detained, but didn’t give further details. Alamgir is the secretary general of the Nationalist Party led by former Prime Minister Khaleda Zia’s party and Hasina’s main rival. The party denounced his detention.

As per Bangladeshi law, a detainee must appear before a court within 24 hours.

Hossain also said six cases were filed against some 1300 people being investigated for Saturday’s violence. Local reports said Sunday that police had raided the homes of several opposition leaders overnight in the capital, Dhaka.

Home Minister Asaduzzaman Khan told reporters that leaders of Zia’s party have to bear responsibility for their “role” in the violence, the United News of Bangladesh agency reported.

Sporadic violence was witnessed Sunday with at least three vehicles set on fire in the capital amid tight security.

The European Union and the United States have denounced the violence on Saturday and urged all to maintain restraint.

The EU delegation in Dhaka said on X, formerly known as Twitter, that it is “deeply saddened to see the loss of life” while stressing that a peaceful way forward was crucial.

The U.S. assistant secretary of State for South and Central Asian Affairs, Donald Lu, called for calm and restraint saying they “will review all violent incidents for possible visa restrictions.”

Tensions in the South Asian country, a parliamentary democracy, are soaring ahead of the national elections, expected to be held in January.

The rivalry between Hasina and Zia has been ongoing for decades, and Hasina’s government has been under pressure for months as the opposition has held largely peaceful anti-government demonstrations.

Hasina hopes to return to power for a fourth consecutive term and says the election should be held under her government’s supervision as specified in the constitution amid a warning by the U.S. of possible visa restrictions for disrupting the election process. The visa restriction policy is primarily focused on law enforcement agencies, as well as the ruling and opposition parties.

The prime minister recently told parliament that the U.S. wants to remove her from power at any cost. However, the opposition and critics have welcomed the move by the U.S., which is the largest importer of Bangladesh’s garment products.

Experts say despite the diplomatic row, both Bangladesh and the U.S. have expanded their bilateral engagement with Hasina looking for ways to bolster trade and other relations with China, India, Russia, the EU and France apart from its traditional partnership with Japan, South Korea and Saudi Arabia.