RAWALPINDI, Pakistan (AP) — A Taliban suicide bomber blew himself up near Pakistan's main military headquarters on Monday, killing 13 people just a day after the militants killed 26 troops inside an army compound in the northwest of the country, officials said.

The two-day barrage against the Pakistani military underscores the challenges it faces in dealing with a stubborn insurgency in tribal regions that border Afghanistan, which has already resulted in thousands of troops dead and wounded.

The twin assaults, both claimed by the Pakistani Taliban, will also put pressure on the right-leaning civilian government that has said repeatedly it would rather negotiate with militants than use military force to end the conflict.

Monday's attack took place early in the morning in the garrison city of Rawalpindi, next to the capital of Islamabad, just a few hundred meters (yards) from the outer wall surrounding the Pakistani military's headquarters.

Eight of the dead were members of the security forces, the Pakistani military said in a statement.

The suicide bomber was riding a bicycle and detonated his explosives when he got close to a military checkpoint, said police officer Haroon Joiya. The area is home to numerous military installations and buildings.

A wrecked bicycle lay on the street that was littered with broken glass and blood.

"My son was 15 minutes late, on his way to college," said Mushtaq Ahmad, an elderly man whose son, Mubashar Mushtaq, died in the blast. Speaking to a local television, Ahmad said: "I told him he was late, but he said he will make it on time."

Sunday's bombing was even more deadly. Security officials said a bomb in a vehicle in a convoy about to leave a military base in the town of Bannu and drive west to the North Waziristan tribal area exploded, killing 20 paramilitary troops. The attack also wounded 30 additional soldiers.

Six of the injured troops died in military hospitals overnight raising the death toll to 26, said two security officials who spoke on condition of anonymity because they were not authorized to speak to the media.

The Taliban has claimed responsibility for both blasts and called the Sunday explosion in Bannu a suicide bombing. Military officials said the blast came from an explosive device planted in the vehicle, hired by the paramilitary Frontier Corps. While the army has its own transport vehicles, the paramilitary forces often hire vehicles when making large troop movements.

A spokesman for the Pakistani Taliban, Shahidullah Shahid, told The Associated Press by telephone that Sunday's attack had been carried out to avenge the death of Waliur Rehman, the group's former second in command. He was killed last year in a U.S. drone strike. Shahid said in a separate telephone call that the Monday bomber was targeting the army.

The Pakistani military has been fighting for years in the tribal areas against militants who want to overthrow the government and establish a hard-line Islamic state. The tribal region is also a refuge for insurgents fighting NATO and U.S. forces in neighboring Afghanistan.

But the new government of Prime Minister Nawaz Sharif, elected last May, has promised to end the fighting through peace talks and a consortium of Pakistani political parties endorsed that idea last September. The idea of a negotiated settlement has support among many Pakistanis who are tired of the ongoing conflict that many view as being pushed on them by the U.S.

So far the Pakistani Taliban have shown little desire to negotiate with the government and ruled out talks after a U.S. drone strike killed leader Hakimullah Mehsud on Nov. 1. They've also put heavy preconditions on any peace talks, including the end of U.S. drone strikes.

In their statement on Sunday, the Taliban said they would be open to talks with the government — but only if the government proved it was sincere and had enough "power," a reference to the perception that the army wields the real power in Pakistan.

While the Pakistani army has carried out repeated operations across the tribal regions, they have been reluctant to launch an offensive against the militants in their stronghold of North Waziristan on the pretext that their forces are too thinly stretched.

The army also appears to be waiting for the civilian government's support of any large-scale offensive in North Waziristan. Such an offensive could result in a large backlash of militant attacks against targets in the relatively peaceful areas of Punjab province.

Sharif has cancelled plans to go to the Davos economic forum following the recent spate of attacks.

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Shahzad reported from Islamabad. Associated Press writer Ishtiaq Mahsud in Dera Ismail Khan, Pakistan, contributed to this report.