Strongly condemning the terrorist attack at the Karachi international airport, the US has offered assistance to Pakistan into investigating the incident. 

"We have offered assistance to the relevant Pakistani authorities investigating this heinous crime," a State Department spokesperson told PTI. Both the White House and the State Department offered deepest condolences to the attack. 

 "The United States condemns the attack on the Karachi airport. Our hearts go out to the families of the victims and those who were wounded in that attack," White House Deputy Press Secretary Josh Earnest, said yesterday. "We extend our deepest condolences to the families and friends of the victims of Sunday's brazen attack on Karachis Jinnah International Airport. We wish those who were injured a full and speedy recovery," State Department Spokesperson, Jen Psaki, said. 

 "The United States condemns this brutal attack and stands steadfast in its commitment to the people of Pakistan in their efforts to counter terrorism and build a peaceful future.  We support Pakistan's efforts to bring all those involved in planning and executing this attack to justice," she said in a statement. The State Department Deputy Spokesperson, Marie Harf, said the United States works very closely with the Pakistani Government on counterterrorism.

"There are a number of groups operating in – particularly in the cross-border area.  We've worked with them for many years, because of course, the Pakistani people themselves have been, as we just saw, tragically the victims of many of these terrorist attacks," she said in response to a question.

The United States, she said, is concerned about different groups operating there, including the Pakistani Taliban. "But we do know the Pakistani Government has a responsibility and an obligation to protect its citizens and to take appropriate counter terrorism measures," she said. 

Refraining from making any comment on the airstrike being carried by the Pak Army against Tehrek-e-Taliban Pakistan (TTP) hideouts in the tribal areas of Pakistan, Harf said it is for Islamabad to decide as to the kind of counter terrorism measures it wants to take against terrorists. "I think that terrorist groups like the TTP should stop attacking innocent civilians.

 I think the Pakistani Government has a responsibility to protect their people and that there's no equivalency between the two in any way," she said. "We've offered to the relevant Pakistani authorities, but more broadly speaking, we work very closely, as you know, with a host of folks in Pakistan on the counter terrorism threat.  Whether it's military, intel, diplomatic, we have a very wide-ranging bilateral relationship on this issue specifically," she said.

Harf said as the Pakistanis undertake counter terrorism operations, the US has worked with them, or at least advised them, to take civilian life into account. 

"Innocent civilians are the targets of these terrorists.  The government's job is to protect their people, so that's what the Pakistani Government is doing.  They're determining the best way to do that, period," she said.