Abdul Qayum Khan, the chief of Khakrez district in northern Kandahar province, said the police were killed and four others were wounded while traveling south by vehicle to Kandahar.
NATO said two US service members died in separate blasts in the south, but provided no other details. The US death toll has mounted in recent weeks as American troops try to extend their reach in the southern provinces of Kandahar and Helmand, while insurgents have mounted a summer counteroffensive aimed at both international troops and the Afghan government.
June was the deadliest month for US and international forces with the deaths of 103 service members, including 60 Americans. Including Monday's deaths, 57 NATO troops have been killed so far this month in Afghanistan, 42 of them American.
The capital city of Kabul has also seen attacks ahead of an international conference on Tuesday, at which the Afghan government hopes to show world leaders it is making progress toward running its own affairs.
Thousands of Afghan soldiers and police have been deployed to secure the capital during the one-day meeting. Officials worry Tuesday's conference will draw a repeat of the violence seen at a national peace gathering in May, when two militants were killed in a gunbattle with security forces and a rocket landed with a thud about 100 meters from the meeting site.
Meanwhile, US Secretary of State Hillary Rodham Clinton, flying into Afghanistan for the conference, said the Obama administration is pressing for better efforts to combat corruption.
Clinton landed in Kabul on Monday after two days of talks in neighboring Pakistan where she pushed officials to work more closely with the government of Afghan President Hamid Karzai in the fight against extremists. Before landing, Clinton told reporters the Kabul conference "is going to show more Afghan ownership and leadership, which is something we've been pushing." Clinton said that she is concerned about reports of the diversion of US aid, but said the problem isn't just with the Afghan government.
"We also have to take our hard look at ourselves because it is very clear our presence, all of our contracting has fed that problem," she said. "This is not just an Afghan problem, it's an international issue. We have to do a better job of trying to more carefully channel and monitor our own aid."
