The Quad grouping of the United States, India, Japan and Australia called on Tuesday for the perpetrators of an Islamist militant attack that killed 26 in India-administered Kashmir to be brought to justice without delay, Reuters reported.

The April 22 attack sparked heavy fighting between nuclear-armed India and Pakistan in the latest escalation of a decades-old rivalry as India blamed it on Pakistan, which denied responsibility while calling for a neutral investigation.

The U.S. State Department issued, opens new tab a joint statement by the foreign ministers of the grouping, who met in Washington, but stopped short of naming Pakistan or blaming Islamabad.

"The Quad unequivocally condemns all acts of terrorism and violent extremism in all its forms and manifestations, including cross-border terrorism," the ministers said in the statement, according to Reuters.