They rewrote computer code to meet last-minute requests for changes from the government.
Russia's move to grant Snowden asylum viewed as negative development for U.S.-Russia relations.
Surveillance programs unearthed by Edward Snowden get their time on Capitol Hill in Washington.
Washington and Moscow still deep in negotiations on NSA leaker Edward Snowden.
President's desire for a comprehensive overhaul with a path to citizenship for millions of illegal immigrants remains the sticking point.
Obama spokesman concedes shifting accounts about who knew what about the tax agency's targeting of conservative groups.
Concerns about efforts to unearth reporters' confidential sources have put Obama in a difficult position.
Explosion is latest in a string of attacks in a week of the most sustained sectarian violence since U.S. troops withdrew more than a year ago.
Presidential spokesman Jay Carney said attendees will include mental health advocates and health care providers.
U.S. tax collection agency admits "inappropriate" focus on conservative political groups in the 2012 election.