WASHINGTON — President Barack Obama is offering the U.S.'s continued support to Pakistan in its fight against extremism after a terrorist attack that killed scores of schoolchildren.

Obama expressed America's condolences in a telephone call Tuesday night with Prime Minister Nawaz Sharif (nah-WAHZ' shah-REEF').

In a brief description of the call, the White House said Wednesday that Obama underscored to Sharif that the American people stand with Pakistan in the face of the tragedy. The leaders also acknowledged the threat they share from terrorism.

Taliban gunmen stormed a military-run school in the city of Peshawar in northwestern Pakistan on Tuesday, killing 148 people. Most were children.

The Taliban said the attack was revenge for a military offensive against their safe havens in the northwest, along the border with Afghanistan.