A bombing in Peshawar kills 117 and wounds 213.

Militants in Pakistan and Afghanistan punctuated Secretary of State Hillary Rodham Clinton’s arrival here with deadly attacks on Wednesday, underscoring their ability to cause chaos even in the face of offensives on both sides of the border.

In Pakistan, a devastating car bomb tore through a congested market in the northwest city of Peshawar, killing as many as 101 people, many of them women and children. Pakistani authorities said the attack was the country’s most serious in two years, and the deadliest ever in Peshawar, which has become a front line for Taliban efforts to destabilize the government through violence.

In the Afghan capital, Kabul, Taliban militants stormed a guesthouse, killing five United Nations employees and three other people in a furious two-hour siege. The attack was meant to scare Afghans away from voting in a runoff election on Nov. 7 between President Hamid Karzai and his challenger, Abdullah Abdullah, a Taliban spokesman said.

The violence cast a shadow over the visit of Mrs. Clinton, who was meeting with government ministers in Islamabad, 90 miles southwest of Peshawar, when news of the Peshawar explosion came over television screens. Mrs. Clinton immediately condemned the bombing, which in killing women and children in Peshawar seemed aimed at the very constituencies she has championed in her travels to other developing countries.

“These attacks on innocent people are cowardly; they are not courageous, they are cowardly,” Mrs. Clinton said at a news conference with the Pakistani foreign minister, her voice raw with anger.

“They know they are on the losing side of history,” she said of the militants. “But they are determined to take as many lives with them as their movement is finally exposed for the nihilistic, empty effort it is.”