Passage: Governments are also getting online. Some countries, such as those of Cuba, Iran, North Korea, Myanmar, the People's Republic of China, and Saudi Arabia use filtering and censoring software to restrict what people in their countries can access on the Internet. In the United Kingdom, they also use software to locate and arrest various individuals they perceive as a threat. Other countries including the United States, have enacted laws making the possession or distribution of certain material such as child pornography illegal but do not use filtering software. In some countries Internet service providers have agreed to restrict access to sites listed by police.

Question: In various countries, what type of companies sometimes limit access to specific websites that are on police lists?
Internet service providers