"President Karzai will no longer be coming to London. He is flying back to Afghanistan following today`s events," Hanif Aman, a spokesman for the Afghan embassy in London, told AFP.
Karzai had been due to arrive in London late Tuesday from Germany for talks with Prime Minister David Cameron.
A spokeswoman for Cameron`s Downing Street office told AFP: "I can confim that President Karzai has cancelled his visit."
A statement from Karzai`s office in Kabul said that on his return, he was to meet the families of victims of the attacks on Shiite shrines in the capital and the northern city of Mazar-i-Sharif.
"President Karzai has cancelled his trip to London due to today`s terrorist attacks. President Karzai, who was in Bonn, was due to visit London this afternoon," it said.
"But learning about two suicide attacks in Kabul and Mazar-i-Sharif, he cancelled his trip to London and headed back to Afghanistan.
"He is due to meet with families of victims when in Afghanistan to express his grief and share his sympathies."
At a press conference with German Chancellor Angela Merkel earlier Tuesday in Berlin, Karzai said the bombings were the first "terrorist" attacks of their kind on the Shiite holy day of Ashura.
The attacks occurred just a day after an international conference in Bonn on the future of Afghanistan after NATO troops pull out at the end of 2014, and raised fears of possible sectarian tensions.
(U.S008)
Editor: Priyambodo RH
Copyright © ANTARA 2011
