A U.S. State Department official has expressed concern over a Turkish security bill that would expand police rights to use firearms and to search and detain people.

The official, Thomas Melia said Friday that the bill which is being debated in Turkey's parliament could lead to "over-zealous prosecution" and strong police measures against peaceful protests.

Speaking with reporters in Ankara, Melia also voiced concern about the prosecution of people who criticize President Recep Tayyip Erdogan.

Human Rights activists say 80 people face legal action for comments or social media postings deemed to be "insults" to Erdogan.

"People in a free society are allowed to complain about their leaders and their performances," said Melia, the deputy U.S. assistant secretary of state in the Bureau of Democracy, Human Rights, and Labor.