"During the meetings with Karzai after August 20 presidential election in Afghanistan, the US Special Envoy to Afghanistan and Pakistan Richard Holbrooke has asked Karzai to agree with an election runoff and form a coalition government after that," an informed source told FNA on the condition of anonymity.
The source reiterated that Holbrook has also urged Karzai to form the coalition with the former Finance Minister, Ashraf Ghani Ahmadzai, and appoint him to the Chief Executive post.
It has been reported that Ashraf Ghani is the US favored candidate for a chief executive spot in Afghanistan.
US plans to push for a western-style chief executive to work under the president which Afghan analysts say is like a Prime Ministerial post.
Holbrook also has asked Karzai to bring other opposition figures and presidential rivals into his cabinet.
Meantime, BBC reported that Holbrooke had an 'explosive' meeting with Afghan President Hamid Karzai recently.
Holbrooke is said to have challenged Karzai over allegations of ballot-stuffing and fraud and called for a run-off to decide the next president.
Karzai reportedly reacted angrily to Holbrooke's criticisms, which also focused on deals struck by the incumbent president with warlords in a bid to garner support before the election.
The tense meeting, held on the day after the poll, was said to have been noticeably briefer than a discussion Holbrooke held with Karzai's main rival for president, Abdullah Abdullah.
Abdullah and international observers have been critical of the conduct of the vote.
With 17% of the votes counted, Karzai had 45% of the votes compared with Abdullah's 35%, according to the official election commission. The final election result is not expected until 17 September, with a preliminary result expected between 3 and 7 September.