The White House and the Pakistani military are confirming that top Taliban commander Mullah Abdul Ghani Baradar is in custody.
White House spokesman Robert Gibbs called the joint U.S.-Pakistan operation that captured him in Karachi several days ago "a big success for our mutual efforts in the region." He declined to discuss details about Baradar's ongoing interrogation, but said his capture is a sign of increased cooperation in the region.
Pakistan's military confirmed Baradar's capture earlier Wednesday.
Baradar, an Afghan national, holds the second most important position within the Taliban, after only the group's founder, Mullah Muhammad Omar.
U.S. President Barack Obama met with top U.S. officials in Washington Wednesday to discuss the situation in Pakistan and Afghanistan.
Mr. Obama's spokesman said he received briefings from U.S. ambassadors in both countries, as well as an update from General Stanley McChrystal about the anti-Taliban offensive in southern Helmand province.
Officials describe Baradar as the most important Taliban figure captured since the start of the war in Afghanistan in late 2001.
In the past, U.S. officials have accused Pakistan's intelligence agencies of maintaining ties with the Afghan Taliban leadership, and of being reluctant to pursue fugitives in Taliban sanctuaries inside Pakistan. Authorities in Islamabad have denied those claims.
Some information for this report was provided by AP and Reuters.