U.S. Secretary of State John Kerry on Tuesday praised the Pakistani military's operation against militants in the country's northwest, saying the results are "significant."

His comments came during a meeting in Islamabad with Sartaj Aziz, the Pakistani prime minister's adviser on foreign affairs.

Pakistan launched a major operation in the North Waziristan region in June. The U.S. had long advocated for such an operation because the region had become a hub for militant groups who attack targets in both Pakistan and neighboring Afghanistan and a source of tension between the U.S., Afghanistan and Pakistan.

The current operations "in the northwest have disrupted militant activities in the tribal areas and resulted in important seizures of weapons," Kerry said. "The operation is not yet complete but already the results are significant. Pakistani soldiers and their commanders deserve enormous credit."

Kerry also announced that $250 million in previously appropriated money will be given to emergency relief efforts in the tribal areas, mainly North Waziristan. Hundreds of thousands of people fled the area due to the fighting.

Kerry also praised the reopening Monday of the school in Peshawar where Taliban gunmen on Dec. 16 slaughtered students and teachers in one of the country's worst terrorist attacks. Kerry called it a testament to the resolve of the Pakistani people.

The secretary arrived in Pakistan on Monday and met with Aziz as well as Prime Minister Nawaz Sharif.

Kerry is making the case for more robust efforts against all extremist groups in the country, particularly after the Peshawar school attack that killed 150 people, most of them children.

Pakistan has boosted operations against violent extremists in recent months. But U.S. officials traveling with Kerry said Washington wants to ensure that there is a "real and sustained effort" to limit the abilities of the Pakistani and Afghan Taliban, the Haqqani Network and Laskhar e Tayyiba, which pose direct threats to Afghanistan, Pakistan and India, as well as to American interests.

Pakistan has been on edge ever since the Dec. 16 attack that was claimed by the Pakistani Taliban as retaliation for the North Waziristan army operation. In response, Pakistan boosted operations in the rugged tribal areas, reinstituted the death penalty for terrorists and moved to try civilian terror suspects in military courts.

Kerry welcomed the strong consensus among Pakistani officials about the need to combat militancy but warned that the work wasn't finished.

"Make no mistake, the task is a difficult one and it is not done," he said.

Aziz defended steps Pakistan had taken after the school attack, saying action was being taken against all militant groups.

Pakistan has often been accused of having a "good Taliban, bad Taliban" policy, meaning they tolerate or support some militants they find useful as proxies in Afghanistan or India and battle other militants who target the Pakistani state. Pakistani officials insist they go after all militants.

The two men also discussed relations with neighboring Afghanistan, with which Pakistan has often had tense relations.

Kerry spoke of the need to help Afghanistan recover from years of instability and he welcomed Pakistan's stated intent to support Afghan-led reconciliation with the Taliban.

Aziz said the U.S. and Pakistan have a "common interest in a united, stable and prosperous Afghanistan" and said Pakistan supports reconciliation but stressed that it was also critical to "make sure Afghan soil cannot be used to undercut" the fight against terrorism.

Kerry also maintained that it was important not to view the U.S.-Pakistan relationship only through the prism of counterterrorism and security. He noted that the United States has provided significant assistance to Pakistan to improve its infrastructure, including roads and power generation.

Between 2009 and 2014, the U.S. provided Pakistan with more than $4.38 billion in civilian assistance, including more than a billion in humanitarian aid.

Kerry and Aziz also addressed the recent heightened tensions along the Pak-India de-facto border of the disputed region of Kashmir. Both Pakistan and India have accused the other of indiscriminately firing across the disputed boundary. Two of the three wars India and Pakistan have fought have been over Kashmir, and any increase in cross-border attacks in the heavily militarized region is generally cause for concern.

"We are concerned about the rise of the number of incidents on the border along the line of control," Kerry said.