A spokesman for the Jamaat-ul-Ahrar terror group said that the attack was meant to target Christians and warned of more attacks to come.
Pope Francis spoke out against the attacks Monday from St. Peter's Square, calling them vile and abominable. He urged Pakistan's leaders to restore peace, especially for religious minorities.
"I repeat, once again, that violence and murderous hatred lead only to pain and destruction; respect and fraternity are the only way to achieve peace," he said, according to Vatican Radio.
Other world leaders expressed their condolences and spoke out against terrorism, as with the attacks in Brussels that killed more than 30 people last week.
The State Department condemned this latest attack "in the strongest terms."
Here's how world leaders reacted to the attack in Pakistan.
U.S. presidential candidates
Republican Donald Trump:
Another radical Islamic attack, this time in Pakistan, targeting Christian women & children. At least 67 dead,400 injured. I alone can solve— Donald J. Trump (@realDonaldTrump) March 27, 2016
Republican Ted Cruz:
The evil that is radical Islamism struck in Pakistan today in a shocking display of savagery: https://t.co/IDjIGTVo8F— Ted Cruz (@tedcruz) March 27, 2016
Republican John Kasich:
"Let us remember the victims ... as we gather strength and resolve to defeat all who threaten our values." pic.twitter.com/vGOoWzQfLH— John Kasich (@JohnKasich) March 27, 2016
Democrat Bernie Sanders:
We are grieving today for the families affected by the deplorable attack in Lahore. No one should ever fear taking their children to a park.— Bernie Sanders (@BernieSanders) March 27, 2016
Democrat Hillary Clinton:
My prayers are with the victims of the horrific Easter Day attack in Lahore. Pakistan and all nations must confront & defeat terrorists. -H— Hillary Clinton (@HillaryClinton) March 28, 2016
Nobel Peace Prize winner Malala Yousafzai, who survived after being shot by the Taliban in 2012, issued a statement following the attacks in her home country.
British Prime Minister David Cameron:
I'm shocked by the terrorist attack in Lahore. My thoughts are with the families and friends of the victims. We will do what we can to help.— David Cameron (@David_Cameron) March 27, 2016
Canadian Prime Minister Justin Trudeau:
Canada condemns the deplorable bombing in Lahore, Pakistan. Our thoughts and prayers are with all those killed or injured. #LahoreBlast— Justin Trudeau (@JustinTrudeau) March 27, 2016
French President Francois Hollande tweeted in French that France stands in solidarity with the people of Pakistan in their time of sorrow.
A la suite de l'attentat à Lahore au Pakistan, j'exprime au peuple du Pakistan toute la solidarité de la France dans ces moments douloureux.— François Hollande (@fhollande) March 27, 2016
Indian Prime Minister Narendra Modi:
Heard about the blast in Lahore. I strongly condemn it. My condolences to families of the deceased & prayers with the injured: PM— PMO India (@PMOIndia) March 27, 2016
King of Jordan:
His Majesty King Abdullah II offers his condolences to the President of Pakistan over the terrorist attack in Lahore #Jordan— RHC (@RHCJO) March 27, 2016
The Associated Press contributed to this report.