ISLAMABAD, Pakistan (CNN) — Gen. David Petraeus, the head of U.S. Central Command, was in Pakistan on Monday for meetings as the Pakistani military battled Taliban militants in the country's northwest, U.S. Embassy officials said.
Also in Pakistan, on a separate visit, was U.S. Sen. John Kerry, who chairs the Senate Foreign Relations Committee.
Details about their visits were not immediately available.
Petraeus' and Kerry's arrivals came of the heels of Pakistani troops launching a massive ground offensive backed by air power over the weekend in South Waziristan, a refuge and a power base for insurgents operating in Pakistan and along the Pakistani-Afghan border.
The highly anticipated offensive follows a wave of suicide attacks in Pakistan and has prompted the exodus of tens of thousands of civilians, a U.N. refugee agency said.
Though the offensive is not the first, it is the most important, Pakistani military spokesman Major Gen. Athar Abbas told CNN, "because we have concluded that this area has become the center of gravity of the problem."
One military official said Pakistani troops had seized control of Kotkai, the home village of Pakistani Taliban leader Hakimullah Mehsud and Taliban commander Qari Hussein. Hussein masterminded some of Pakistan's deadliest suicide attacks.
Strikes by jet fighters and helicopter gunships targeted militant hideouts in Kotkai and the villages of Badar, Barwand and Khisur — all strongholds of the Taliban and their late leader Baitullah Mehsud, another official told CNN.
The officials spoke on condition of anonymity because they were not authorized to speak to the media.
For months, the military have targeted militant hideouts in South Waziristan and other hotspots in Pakistan's tribal areas. Earlier this year, troops launched a large operation targeting militants in the Swat Valley, in Pakistan's North West Frontier Province.
Despite such efforts, insurgents have continued to strike with relative impunity in Pakistan, targeting government, police and security locations.
The recent wave of deadly attacks has raised concerns about the ability of Pakistan's security forces to maintain control. The violence also has heightened internal and international pressure on the government to take swift and effective action.
Pakistani officials said about 10,000 to 15,000 militants linked to the Taliban or to al Qaeda operate in South Waziristan, a harsh terrain familiar to militants but difficult for others to navigate. About 28,000 Pakistani soldiers have moved into the epicenter of Taliban activity in the region to counter their activities, officials said.