Clinton was speaking a day after accusing Islamabad of foot-dragging in the case of Hafiz Saeed, the Pakistan-based Islamist blamed for masterminding the attack by gunmen on Mumbai, India's financial capital, in 2008. Clinton has authorized a $10 million reward for information leading to his capture.
"We look to the government of Pakistan to do more," Clinton told a joint news conference with Indian Foreign Minister S.M. Krishna on Tuesday as she wrapped up an eight-day Asian trip that also took her to China and Bangladesh.
"It needs to make sure that its territory is not used as a launching pad for terrorist attacks anywhere, including inside of Pakistan, because the great unfortunate fact is that terrorists in Pakistan have killed more than 30,000 Pakistanis," she said.
Clinton said there was a need for wider vigilance against militant attacks, pointing to the discovery of a new plot linked to the Yemen-based group, al Qaeda in the Arabian Peninsula, to attack an airliner with an improved "underwear bomb".
"The device did not appear to pose a threat to the public air service, but the plot itself indicates that these terrorists keep trying, they keep trying to devise more and more perverse and terrible ways to kill innocent people," she said.
U.S.-PAKISTANI TIES FRAYED
Relations between the United States and Pakistan sharply deteriorated after a series of incidents fuelled mistrust between the two uneasy allies in the war on Islamist militancy.
The incidents included Pakistan's arrest of a CIA contractor in early 2011, the top-secret U.S. raid that killed Osama bin Laden just 50 km (30 miles) from Islamabad a few months later, Pakistan's fury over U.S. drone strikes and a U.S. air assault in November 2011 that killed 24 Pakistani soldiers along the border with Afghanistan.
Pakistan disputes the charges of inaction, saying it has suffered more casualties than any other country in fighting the Pakistani Taliban, other militant groups along the Afghan border and Islamist groups inside the country.
Both Washington and New Delhi have criticized Pakistan for not detaining Saeed, who founded the militant group Lashkar-e-Taiba (LeT) in the 1990s. He denies any wrongdoing and links to militants.
India blames the LeT for the Mumbai attacks in which Pakistani gunmen killed 166 people over three days and says Pakistan is also a haven for militants operating in Afghanistan.
India has said that Pakistani action on the Mumbai attackers is central to tentative peace moves between the nuclear-armed rivals, which have fought three wars since their independence in 1947.
The Indian foreign minister joined Clinton in calling for Pakistan to get tougher with militants within its borders.
"Recent attacks in Kabul highlight once again the need for elimination of terrorist sanctuaries in the neighborhood and the need for stronger action from Pakistan on terrorism, including on bringing to justice the perpetrators of (the) Mumbai terrorist attack," Krishna said.
The US ambassador to Afghanistan last month blamed an assault on embassies and parliament in the Afghan capital, Kabul, on the al Qaeda-linked Haqqani network, whose fighters move freely across the Afghanistan-Pakistan border, and reiterated a long-standing demand that Islamabad go after the group.
After a similar attack last year, the outgoing chairman of the US Joint Chiefs of Staff called the Haqqani group a "veritable arm" of Pakistan's intelligence service.
Pakistan denies claims that it sees the Haqqanis as a strategic asset to counter the influence of India in Afghanistan.