The U.S. Senate has blocked a measure to extend provisions of the USA Patriot Act that allow the National Security Agency (NSA) to collect bulk telephone records of U.S. citizens.
By a vote of 54-45, the Senate failed to reach the 60-vote threshold needed to advance a bill that would have extended the program for two months.
The vote leaves the fate of the program uncertain days before it is set to expire on June 1.
The highly controversial data-collection program was exposed two years ago by former NSA contractor Edward Snowden, who is now living in Russia.
The measure was opposed by some members of President Barack Obama's Democratic Party and the Republican Party, who say the program is too intrusive into the private lives of average citizens.
Supporters say the program is a valuable surveillance tool.
Based on reporting by AP and Reuters
