The United States is failing to address the threat of bioterrorism, according to leaders of a bipartisan panel that warns that an attack worldwide is more likely than not by the end of 2013.

The Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism, created by Congress in 2007, said in an interim report Wednesday that the administration and lawmakers have underfunded efforts to develop vaccines and drugs and have not named a high-level National Security Council appointee to improve biodefenses.