Dec 5 (Reuters) - The House Committee on Homeland Security has asked Google and Apple to detail what steps they are taking to remove mobile applications that allow users to track federal immigration officers.

In letters sent on Friday to Google CEO Sundar Pichai and Apple head Tim Cook, committee leaders singled out ICEBlock, an app previously used to monitor U.S. Immigration and Customs Enforcement agents, saying apps hosted on their app stores risk "jeopardizing the safety of DHS personnel." Lawmakers requested a briefing by December 12.