Ambassador Muhammad Husain Adeli on Wednesday also said that Tehran was ready to work again with the US to ensure stability in the Middle East when their interests converged.
"For the recent elections, there was not only implicit but explicit indirect and direct cooperation between the two, Iran and the United States, in order to keep the majority calm and in favour of the election," Adeli said.
Tehran and Washington have not had diplomatic links since the 1979 Islamic revolution and relations between them are currently tense.
But Adeli said they had worked through diplomatic channels, including Britain, to promote their common interests in successful elections in Iraq.
"For the recent elections, there was not only implicit but explicit indirect and direct cooperation between the two, Iran and the United States, in order to keep the majority calm and in favour of the election"
Muhammad Husain Adeli, Iranian ambassador to the UK
Adeli said Iran had campaigned in favour of the elections not only with the Shia in Iraq but had also tried to persuade Sunnis that the poll was in their interests.
"We encouraged them that this is a process in favour of Iraq."
Adeli added that before the Iraqi elections Iran and the US had not only "exchanged notes" through interest sections they maintained in the Pakistani and Swiss embassies in Washington and Tehran, but had also worked through London.
He said Tehran and Washington frequently had converging interests. Their common strategic priorities had brought them together during the 2001 US invasion of Afghanistan.
"There was a lot of coordination between the groups that were based in Iran and Iranians, with those of Americans to create the conducive environment for the victory of the forces over there."