Taliban militants who killed 72 people, many of them children, in a brutal Easter weekend bombing mocked Prime Minister Nawaz Sharif on Tuesday with a taunting tweet that declared war had "reached his doorstep".

Taliban militants who killed 72 people, many of them children, in a brutal Easter weekend bombing mocked Prime Minister Nawaz Sharif on Tuesday with a taunting tweet that declared war had "reached his doorstep".

Hundreds were injured when explosives packed with ball bearings ripped through crowds near a children's play area in a Lahore park, where families had gathered to enjoy a warm Sunday evening.

Sharif vowed in a televised address Monday to avenge the attack in the provincial capital, a stronghold for his ruling Pakistan Muslim League.

"Terrorists cannot dent our resolve. Our struggle will continue until the complete elimination of the menace of terrorism," he said.

But on Tuesday Ehansullah Ehsan, spokesman for the Jamaat-ul-Ahrar faction of the Pakistani Taliban that carried out the attack, derided the prime minister on Twitter.

"After the Lahore attack, Nawaz Sharif repeated old words to give himself false assurances," he wrote.

"Nawaz Sharif should know that war has reached his doorstep, and God willing the mujahideen will be the winners in this war."

The attack was the worst so far in 2016 for a country grimly accustomed to atrocities, and will further fray inter-religious ties in the Muslim-majority nation.

In response to the atrocity, the country's powerful army announced it had carried out raids in Lahore as well as in Faisalabad and Multan, two other major cities in Punjab province. More were planned, it said.

Twin suicide attacks against churches in Lahore killed 17 people in March last year, sparking two days of rioting by thousands of Christians.