WASHINGTON, May 6 (Xinhua) -- U.S. President Barack Obama met with Pakistani President Asif Ali Zardari and Afghan President Hamid Karzai at the White House on Wednesday, with the three sides pledging to continue cooperation in the fight against extremism and terrorism.

    Speaking to reporters after separate talks with Zardari and Karzai and a joint meeting with the two leaders, Obama said that the two leaders "fully appreciate the seriousness of the threats that we face" from extremists and are committed to confronting it.

U.S. President Barack Obama, Afghanistan's President Hamid Karzai (2nd L), Pakistan's President Asif Ali Zardari (3rd L) and U.S. Vice President Joe Biden (L) leave after meeting the press at the White House in Washington May 6, 2009

In his short statement about the talks, Obama also pledged to work with Islamabad and Kabul to avoid civilian casualties when liquidating insurgents in the two countries.

    U.S. Secretary of State Hillary Rodham Clinton, who met with Zardari and Karzai earlier in the day, also expressed deep regrets over the loss of life in the anti-terror operation.

U.S. President Barack Obama (C) talks to reporters as Afghanistan's President Hamid Karzai (2nd L), Pakistan's President Asif Ali Zardari (R) and U.S. Vice President Joe Biden stand on at the White House in Washington May 6, 2009

    It was reported that more than 100 Afghans, including women and children, were killed in U.S.-led air strikes on Monday.