One of the improvised explosive devices was planted along the route of an army convoy in the Mir Ali area 35 kilometres east of Miranshah, they said.
"The explosion killed at least two soldiers and injured seven others," a security official in Miranshah said on condition of anonymity.
Another local security official confirmed the attack and said two of some 10 to 15 vehicles in the convoy were severely damaged.
In the Shin Qamar area of the Khyber tribal region, at least three labourers were killed and three wounded Sunday in an explosion caused by a roadside bomb, said senior local official Nasir Khan.
He said the bomb went off as the labourers, who were carrying construction materials on mules, passed by. Local intelligence officials also confirmed the incident.
The tribal belt is made up of seven districts. In North Waziristan, Taliban and al Qaeda-linked militants have carved out strongholds used to plot attacks across the border in Afghanistan.
The al Qaeda-linked Haqqani network in North Waziristan, blamed for some of the deadliest attacks in Afghanistan, is one of the thorniest issues in relations between Islamabad and Washington.
Washington has long demanded that Pakistan take action against the Haqqanis, which the then-top US military officer, Admiral Mike Mullen, last year described as a "veritable arm" of the Pakistani intelligence service.
Pakistan says it will act according to its own needs and priorities and not on the wishes of a foreign government.
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