QUETTA, Pakistan — A bomb targeting paramilitary soldiers killed 12 people in southwest Pakistan on Thursday, while five suspected militants died in a U.S. drone strike in the country’s northwest, officials said.

Separately, an explosion ripped through a crowded mosque in the northwest city of Mingora, killing 21 people and injuring more than 70 others, said hospital official Mian Gul Aleem. The blast was caused by a gas cylinder that exploded, said senior police official Gul Afzal Khan.

The drone strike was the seventh in two weeks, one of the most intense series of attacks in the past two years. During that period, political tensions between the U.S. and Pakistan led to a reduced number of strikes compared to 2010, when they were at their highest.

It’s unclear whether the current uptick has been caused by particularly valuable intelligence obtained by the CIA, or whether the warming of relations between the two countries has made strikes less sensitive. Protests by the government and Islamic hardliners have been noticeably muted.

The U.S. views drone attacks as a key weapon against Taliban and al-Qaida militants out of its forces’ reach in Pakistan’s tribal region. But the attacks are extremely unpopular in Pakistan, posing a problem for the Pakistani government, which has played a double game in the past of denouncing the strikes in public while supporting some of them in private.

The strike on Thursday occurred in a village near Mir Ali, one of the main towns in the North Waziristan tribal area, said Pakistani intelligence officials, speaking on condition of anonymity because they were not authorized to talk to the media.

North Waziristan is located next to the Afghan border and is the main militant sanctuary in Pakistan. The U.S. has repeatedly pushed Pakistan to launch a military offensive in the area, but Islamabad has refused, saying its troops are stretched too thin fighting domestic militants who pose a threat to the state.

However, many analysts believe Pakistan is reluctant to target Afghan Taliban militants with whom it has historical ties and who could be useful allies in Afghanistan after foreign forces withdraw. Pakistan is also worried about potential backlash from militants who have so far directed their fight against coalition forces in Afghanistan rather than the Pakistani state.

Thursday’s strike occurred in an area dominated by powerful militant commander Hafiz Gul Bahadur, who is believed to have a nonaggression pact with the Pakistani military.

A drone attack on Jan. 2 in the neighboring South Waziristan tribal area killed another such commander, Maulvi Nazir, who also had a truce with the Pakistani army. His death could complicate the military’s fight against Pakistani Taliban militants in the area who have been waging a bloody insurgency against the government for the past few years.

The Pakistani and Afghan branches of the Taliban are allied but have focused their fights against different enemies.

U.S. drone strikes have mainly focused on members of the Afghan Taliban and al-Qaida but have also occasionally targeted the Pakistani Taliban.

U.S. missiles killed nine Pakistani Taliban fighters in South Waziristan on Jan. 6. A drone strike killed the leader of the Pakistani Taliban, Baitullah Mehsud, in South Waziristan in August 2009.

Islamabad has been understandably less opposed to strikes that target the Pakistani Taliban since the group poses a direct threat to the government. It’s unclear whether the most recent strike was part of an effort to reduce government opposition to the drone program in the country.

The government has officially protested many recent strikes, but the response over the past two weeks has been muted. The response from Islamic hardliners, some of whom are believed to have links with the Pakistani military, has also been fairly quiet.

Many Pakistanis oppose the attacks because they believe they mostly kill civilians, an allegation denied by the U.S. Independent research indicates that a majority of those killed are militants, but civilian casualties also occur.

President Barack Obama ramped up drone strikes in Pakistan when he took office in 2009. There were 53 attacks that year, more than in the previous five years combined, according to the Long War Journal website, which tracks the strikes. Since Dec. 28, there have been seven drone attacks, according to an Associated Press count. The AP counts an attack that hits multiple adjacent targets as a single strike.

The annual tally of attacks peaked in 2010 at 117 but declined over the next two years as tension between the U.S. and Pakistan increased, especially over the covert raid that killed Osama bin Laden in the Pakistani town of Abbottabad in May 2011, and the accidental death of 24 Pakistani troops in U.S. airstrikes in November 2011. There were 64 attacks in 2011 and 46 in 2012, according to the Long War Journal.

Relations between the U.S. and Pakistan have slowly improved during the past six months after the U.S. apologized for the deaths of the Pakistani soldiers.

The bomb that exploded Thursday in a commercial area in Quetta, the capital of southwest Baluchistan province, was placed near a vehicle carrying paramilitary soldiers, said Akbar Hussain Durrani, the provincial interior secretary. The bomb was concealed in a bag that was spotted by a local resident. But before the soldiers could react, it was detonated by remote control, said Durrani.

The blast killed 12 people and wounded 47 others, including seven soldiers, said senior police officer Hamid Shakeel. No group has claimed responsibility for the attack.

Baluchistan has experienced a decades-long insurgency by nationalists who demand greater autonomy and a larger share of the province’s natural resources. It is also home to many Islamist militants, including the Taliban.