USA

NASA postponed the launch of the shuttle Discovery after engineers found a fuel sensor malfunction only hours before the scheduled liftoff Wednesday afternoon. If the cause of the problem can be determined and repaired, the next launch could occur as early as Saturday or by July 31, officials said. Otherwise, the agency would have to wait until September for Discovery's rendezvous with the International Space Station.

Local governments should assume primary responsibility for protecting passengers on subway, bus, and train lines, Homeland Security Department chief Michael Chertoff said. The federal government's priority, he told a gathering of Associated Press editors and reporters, is the security of commercial airlines because of the greater risks involved and federal oversight of the industry. Still, Chertoff said, his department is looking to technology to detect explosives and biological, chemical, or radioactive materials whose removal would make mass transit safer.

The White House has not given up in pushing for a confirmation vote on John Bolton as US ambassador to the UN, and said Wednesday it wants the Senate to try again to grant an up or down vote to the blunt-spoken nominee. Democrats have held up the nomination process with procedural votes. If the stalemate continues, President Bush could appoint Bolton during the Senate's summer recess to serve until January 2007.

The National Hockey League, which lost its entire 2004-2005 season to a lockout, is expected to return to action after its players and owners reached a tentative contract agreement Wednesday. Details of the deal won't be announced until both parties ratify it, probably next week. The six-year pact is expected to include a salary cap tied to league-wide revenues.

The nation's first wrongful-death trial involving the painkiller Vioxx was set to begin Thursday in Angleton, Texas. The case stems from a lawsuit (one of 3,800 pending against Merck Co.) brought by a widow who alleges that the drug contributed to her husband's death. The painkiller was taken off the market in September after a study linked it to increased risk of heart problems.

US-born Ali al-Timimi, an Islamic scholar who was convicted in April of exhorting his followers to join the Taliban and fight against American troops, was sentenced Wednesday in Alexandria, Va., to life in prison.