A suicide attack in the Pakistani capital, Islamabad, has killed at least 12 people and injured 21 more.

The November 11 attack comes a day after a car bomb killed at least eight people and injured 19 others in New Delhi, the capital of India.

Analysts fear the attacks could trigger renewed tensions between the nuclear-armed archenemies who frequently blame each other for supporting militant and terrorist groups.

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In Islamabad, the Pakistan Institute of Medical Sciences hospital said at least 4 of the injured were in critical condition.

Pakistans Interior Minister Mohsin Naqvi said an assailant detonated explosives near a police vehicle in the district court complex in the heart of Islamabad.

"Everyone started running inside out of panic. I have seen at least five dead bodies lying at the front gate," Mohammed Shahzad Butt, a lawyer who witnessed the attack, told the AFP.

Khorasan Diary, a website tracking militant groups in Pakistan and Afghanistan, said Jamatul Ahrar, an affiliate of the Tehrike Taliban Pakistan (TTP) militant group, claimed responsibility for the attack.

Pakistan has consistently blamed the Taliban ruling neighboring Afghanistan for sheltering and supporting the TTP.

The two went to near war as tensions escalated into intense attacks along their 2,500 kilometer-long (1,500 miles) border last month. For the first time since its independence in 1947, Islamabad launched airstrikes against the Afghan capital, Kabul and the southern city of Kandahar last month.

Talks between the two erstwhile allies have stalled, but a tense ceasefire has been in place for weeks.

In India, Prime Minister Narendra Modi declared the November 10 blast a conspiracy.

"Our authorities will get to the bottom of this conspiracy," he said during a visit to Thimphu, the capital of neighboring Bhutan.

The explosion was the first significant security incident since gunmen killed 26 people at the tourist site of Pahalgam in Indian-administered Kashmir in April.

New Delhi blamed militant groups based in Pakistan for the attack. Indias attack on the alleged hideouts of militant groups in Pakistan-administered Kashmir triggered a near-war between the two in May.