US Secretary of State John Kerry is to visit the Army Public School in Peshawar, Pakistan, where dozens of children were massacred by the Taliban in December 2014.
Kerry, who is currently in India, will go to Pakistan to pay homage to the victims of the terror attack.
The announcement came as Pakistani pupils returned to the school in Peshawar, one month after the attack that killed 150 people, of which 134 were children.
The Taliban claimed responsibility for the attack, saying it was carried out in retaliation to a military operation in which some civilians in remote areas close to the border with Afghanistan were allegedly killed.
The attack at the school - attended mainly by children of army members - was a way to discourage military activity in the area.
"If our women and children die as martyrs, your children will not escape, we will fight against you in such a style that you attack us and we will take revenge on innocents," Umar Mansoor, identified as the mastermind behind the massacre, said in a video released on a website frequently used as a conduit for Taliban messages.
There have been suggestions that the attack also aimed to send a message against the global recognition of Pakistani schoolgirl activist Malala Yousafzai, who was awarded the 2014 Nobel Peace Prize for advocating education for women and children.