“Thoughts and prayers of the people of Pakistan are with the family and friends of Senator McCain ,” said a statement issued by Foreign Office.
The statement further added, “As Chairman of the Armed Services Committee, Senator McCain always stood for strong Pakistan-US relations and a cooperative approach for promoting peace and building stability in the region. He will be greatly missed in Pakistan."
Barack Obama, who beat Mr McCain to the White House in 2008, said they shared a "fidelity to something higher".
George W Bush described him as "a patriot of the highest order".
McCain was diagnosed with an aggressive brain tumour in July last year and had been undergoing treatment.
But on Friday his family announced he had decided to discontinue that treatment.
A statement from his office on Saturday said Mr McCain died in Arizona surrounded by family members.