Military officials say two separate attacks have killed three U.S. soldiers and a French soldier in Afghanistan.
NATO and the U.S. military say two roadside bombs exploded Saturday as a military patrol passed through the southern province of Kandahar, killing three U.S. soldiers.
In a separate incident, the French military says one French soldier was killed during a clash with insurgents north of the capital, Kabul.
July was the deadliest month for international forces in Afghanistan since 2001, with at least 75 coalition troops killed.
Thousands of U.S., British and Afghan troops are taking part in an offensive against the Taliban in southern Helmand province ahead of the August 20 presidential vote.
Saturday, suspected Taliban militants attacked a convoy carrying Afghan President Hamid Karzai's campaign staff in southeastern Ghazni province. Afghan officials say one guard was killed and two people were injured, including a candidate for provincial elections.
It was the latest in a series of attacks on election officials and candidates in recent weeks.
Saturday, Afghan presidential candidate and former foreign minister Abdullah Abdullah told reporters in Kabul that the government was failing in its duty to provide security during the election process.
The Taliban this week vowed to disrupt the upcoming election, urging Afghans to boycott the vote and ordering its fighters to block roads to prevent people from getting to the polls.
President Karzai was not in Ghazni during Saturday's attack, and was instead campaigning in the northern province of Baghlan.
The Afghan leader told supporters in Kayan village that achieving peace will be his top priority if re-elected. He said his second priority will be strengthening ties with the international community, including the United States.
President Karzai is considered a front-runner in the election.
Some information for this report was provided by AFP, AP and Reuters.