KABUL: Insecurity defined Afghanistan's elections and contributed to weaker turnout than four years ago but the presidential and provincial polls were credible, a US-based group of monitors said Friday.

"There is no question that this election was defined by insecurity," said Richard Williamson, who headed a 29-member delegation from the International Republican Institute (IRI) that monitored Thursday's polls.

"No one can dispute that the merchants of insecurity had some success," Williamson told a news conference one day after the elections. Despite some irregularities "so far it has been a credible election".

It was the first news conference by international election monitors in the wake of the presidential and provincial council elections held across Afghanistan on Thursday.

The international community, which has pumped billions into the country since the 2001 US-led invasion ousted the Taliban, welcomed the polling as relatively peaceful. Officials said extremist attacks killed 26 people.

The elections were the third in Afghanistan following the first presidential election in 2004 won by current President Hamid Karzai, and parliamentary and provincial council elections the following year.

The IRI praised "many positive aspects" of the election, including a vigorous and relatively civil campaign.

But it went on: "Unfortunately, such issues as lower turnout, fraud and abuse of state resources brought these elections to a lower standard than the 2004 and 2005 Afghan elections."

The group said its foreign observers monitored more than 150 polling stations and Afghan staff more than another 100.

A survey released by the same organisation before the elections predicted that Karzai may be forced into a second round run-off, winning 44 percent of votes compared to 26 percent for ex-foreign minister Abdullah Abdullah.

The group describes itself as a non-partisan organisation that aims to advance democracy but features prominent US Republicans on its board, such as its chairman, former presidential candidate John McCain.