WASHINGTON—Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, offered a dose of U.S. support for Pakistan’s counterterrorism efforts Thursday, amid a flurry of U.S. criticism of its ally.

Adm. Mullen, who is close to Pakistan’s military chief, said in an interview that Islamabad had gotten the message that it needs to do more to battle militants on its territory, and that he expects a Pakistani attack on terrorist havens in North Waziristan and other tribal areas, though he said he didn’t know when it would occur.

“The danger, not just now but in the future, is this epicenter of terrorism literally in the world, is right there,” Adm. Mullen said in an appearance on The Wall Street Journal’s “The Big Interview” webcast. “They know that is something that has to be by and large eliminated.”

The Obama administration has been increasingly frustrated with Pakistan’s perceived unwillingness to rout militants from key areas of the country’s tribal areas. A White House report recently sent to Congress rendered a particularly harsh judgment on the Pakistan military’s progress against militants in the tribal areas, and said elements of Pakistan’s spy agency were arming the Taliban and pressuring them to continue to fight.

Adm. Mullen has long been the most outspoken member of the U.S. government in support of Pakistan’s military efforts. Adm. Mullen has used his close relationship with Gen. Ashfaq Kayani, the Pakistani army chief of staff, to prod the military to step up its actions against military.

U.S. military officers, including Adm. Mullen, have been against placing too much public pressure on the Pakistani army, arguing such an approach is counterproductive given the fragility of Pakistan’s domestic situation. The country is now coping with major flood damage, which has sapped government and military resources.

But the U.S. has also pressed Pakistan to do more for its own flood relief. On Thursday, Secretary of State Hillary Clinton suggested the European Union should follow the U.S. and withhold further relief aid until Islamabad shows it is doing more to fight corruption and collect tax revenue from its wealthiest citizens.

“The international community can only do so much,” Mrs. Clinton said. It is unacceptable, she said, “for those with means in Pakistan not to be doing their fair share to help their own people.”

EU ministers and Pakistan’s foreign minister are meeting in Brussels Friday to address Pakistan’s flood-relief needs. The World Bank on Thurday tagged the estimated damage from the floods at $9.7 billion. Pakistan has received $1.5 billion in relief so far. The EU has contributed around $500 million, and waived some import duties; the U.S. has given roughly $400 million.

Pakistan has bristled at the increased U.S. pressure for it to do more on the battlefield. Last week, in the wake of a series of cross-border attacks by NATO—including one that killed members of Pakistan’s Frontier Corps—Islamabad temporarily closed a key border crossing.

Adm. Mullen apologized for the deaths of the Frontier Corps members and worked with the Pakistani military to try to quickly normalize relations.

In the interview, Adm. Mullen suggested the best way to eliminate the militant havens was by strengthening the U.S.-Pakistan relationship, and convincing Islamabad that the militants that threaten the U.S. are also a grave danger to Pakistan.

The U.S.-Pakistan relationship has been on something of a roller coaster in recent years. The U.S. decision in the late 1990s to cut off aid to Pakistan after it tested a nuclear weapon eroded relations between the two countries. Since becoming chairman of the Joint Chiefs, Adm. Mullen has worked to rebuild military ties with Pakistan.

“We didn’t have a relationship with them for a period of 12 years,” Adm. Mullen said. “So it has a lot to do with building trust. The expectation we could instantly get to the same place from a standpoint of supporting this is just too much to expect at this point in time.”

Pakistan currently conducts “surgical” raids against militants in North Waziristan—home to the al Qaeda-linked Haqqani network—but has said a large-scale operation to clear the area of all military would threaten Islamabad’s ability to keep militants out of other areas it cleared previously.

Islamabad is willing to step up their surgical raids in North Waziristan if the U.S. provides them with more information about the location of militants they want removed, a senior Pakistan official said this week.

—John W. Miller in Brussels contributed to this article.

Source: The Wall Street Journal