"I strongly condemn the heinous May 13 attack on a bus in Karachi, which resulted in the deaths of dozens of members of the Ismaili community," Secretary of State John Kerry said in a statement.
"The American people stand in solidarity with the people of Pakistan, and with the global Ismaili community on this tragic day. Make no mistake: There is more strength by far in the respect and solidarity that we feel towards one another than there could ever be in any terrorist attack," he said.
"We will support efforts to bring all those responsible to justice and stand ready to provide assistance to the investigation of this tragic attack," Kerry said.