Former Foreign Minister Abdullah Abdullah won the support of Zalmai Rassoul, another former Foreign Minister.

The front-runner in Afghanistan’s presidential election picked up a potentially powerful endorsement on Sunday ahead of a second round of polling later this month.

Former Foreign Minister Abdullah Abdullah, who came out on top according to a preliminary tally in the first round of voting April 5, 2014 won the support of Zalmai Rassoul, another former Foreign Minister.

Speaking together at a news conference, Mr. Rassoul said his decision to back Mr. Abdullah was based on “national unity, stability, peace and prosperity”.

Mr. Rassoul came in third behind Mr. Abdullah and ex-Finance Minister Ashraf Ghani Ahmadzai in the first round. Final results of the first round are due to be announced on Wednesday, with a second round face-off between Mr. Abdullah and Mr. Ahmadzai likely to take place two weeks after that.

Mr. Abdullah garnered 44.9 per cent of the first-round vote, followed by Mr. Ahmadzai with 31.5 per cent. Mr. Rassoul collected 11.5 per cent.

The preliminary results were from about 6.6 million valid votes.

It is unclear whether Mr. Rassoul can deliver the votes of his supporters, who are largely Pashtuns, the country’s largest ethnic group.

If voters follow previous patterns of choosing along ethnic lines, some believe much of the Pashtun vote will coalesce around the candidate who shares their ethnicity in a runoff and many Pashtuns do not view Mr. Abdullah as one of their own, since he has an ethnic Tajik mother and Pashtun father.

Still, Mr. Abdullah who was second place to Mr. Karzai in the 2009 election clearly received some Pashtun support in the first round, and his experienced campaign may draw enough in a second round to put him over 50 per cent.