ISLAMABAD (AP) — Police in eastern Pakistan arrested seven men accused of sexually abusing children and distributing videos of the abuse, authorities said Sunday. More arrests were expected.

Investigators were sifting through evidence, including 18 or 19 videos seized so far, said Kasur district regional police chief Shahzad Sultan.

It was not yet known how many children were abused or if there were other videos, police officer Babar Saeed said.

Police were investigating claims the suspects were blackmailing the victims' families, demanding money in exchange for not making the videos public. Copies of the abuse videos were allegedly sold in local markets.

Punjabi provincial home minister Shuja Khanzada said authorities were rigorously investigating the men in custody and that about 10 other suspects would be arrested soon.

The story gained momentum Sunday as Pakistani media publicized a variety of sordid allegations over the case, which police declined to discuss.

The case became public after victims' families clashed with police last Tuesday, accusing authorities of ignoring their complaints.

Child Protection Bureau chief Saba Sadiq has demanded a high-level judicial probe, while provincial chief minister Shahbaz Sharif ordered investigators to make all the facts public.