PESHAWAR, Pakistan — Three bomb blasts killed 34 people Monday in northwest Pakistan, authorities said. Though no one claimed responsibility for the attacks, they came at a time when government officials have been warning that Islamic militants might try to exploit the strain that this summer’s catastrophic floods have put on the country’s military and government by unleashing a new wave of violence.

One of the attacks occurred in South Waziristan, a tribal area along the Afghan border long regarded as a stronghold for the Pakistani Taliban. A teenage suicide bomber appeared at a mosque in the town of Wana where 200 worshippers were praying and detonated explosives strapped to his body, witnesses said. The blast killed 25 people and injured 36 others, hospital officials said.

Among the dead wasMaulana Noor Muhammad, a former lawmaker and head of the Islamic school where the mosque was located. He had just finished translating verses from the Quran when the blast occurred. Muhammad was a member of the Jamiat Ulema-e-Islam (Fazlur Rehman) party, which historically has been sympathetic to the Taliban movement.

“”I saw a teenager who shook hands withMaulana Noor Muhammadbefore detonating the explosives,”” saidAyub Wazir, a worshipper who survived the blast.

The motive of the attack was unclear. At times, violence in the tribal areas occurs between rival tribal and militant factions.

A second attack occurred in the Kurram tribal district when a remote-controlled bomb exploded in a school where tribal elders had been meeting. The blast, which occurred in the village of Parachamkani, killed six people and injured seven others, authorities said.

The third attack occurred early in the evening on the outskirts of northwest Pakistan’s largest city, Peshawar. A bomb planted in a push cart exploded in the town of Mattani, killing three people and injuring six others, police said.Dilawar Khan, head of a local anti-Taliban militia, said his militia was the target of the attack. Two of the dead belonged to the militia.

In both South Waziristan and Kurram, Pakistani troops have launched offensives over the last year to flush out Taliban militants and re-establish governmental control over the regions. Despite the offensives, pockets of militants remain active in many parts of the tribal areas.

Last week,Mian Iftikhar Hussain, information minister for northwest Pakistan’s Khyber-Pakhtunkhwa province, warned that militants had been regrouping in the tribal areas to take advantage of a time when the state has had to deploy thousands of Pakistani soldiers and police to cope with the ongoing flood crisis, which has killed more than 1,600 people and submerged vast swathes of the country.

In the tribal district of North Waziristan, two U.S. drone missile strikes killed 12 people and injured 15 others, intelligence sources said.

One of the missiles targeted Dandy Darpakhel, an area known as a stronghold of the Haqqani network, a wing of the Afghan Taliban. Among the seven killed were four women, the sources said. The other strike killed five people in the village of Derga Mandai, sources said.