WASHINGTON — Major technology firms have released new data on how often they are ordered to turn over customer information to the government for secret national security investigations, resulting in the collection of data on thousands of Americans.

The publications disclosed by Google, Microsoft, Yahoo, Facebook, LinkedIn and Tumblr provided expanded details about the government’s handling of customers’ Internet data in counterterrorism and related probes. The figures from 2012 and 2013 showed that companies such as Google and Microsoft were compelled by the government to provide information on as many as 10,000 customer accounts in a six-month period. Yahoo complied with government requests for information on more than 40,000 accounts.

Seeking to reassure customers and business partners alarmed by revelations about the government’s massive collection of Internet and computer data, the firms stressed that only small numbers of their customers were targeted by authorities. Still, thousands of Americans were affected by the government requests approved by judges.