MIRAMSHAH, Jan 22 Two people were killed and two others injured when security forces launched a search operation in Machas refugee camp in Miramshah tehsil of North Waziristan on Friday.

A curfew was imposed and at 4am people were ordered on loudspeakers to quit the camp which housed hundreds of Afghan refugees and displaced people.

At 7am, a house-to-house search was carried out.

A man who resisted the security personnel was shot dead. During the operation, helicopter gunships shelled the area twice, destroying four houses. About 50 people were arrested.

Another man was killed and two others injured when troops opened fire at people for violating the curfew on the Miramshah bypass.

AP adds This is Pakistani security forces' first reported foray in North Waziristan where America has been calling for action against Al Qaeda and the Taliban, intelligence officials said.

However, there was nothing to suggest that the action signalled the start of a major offensive.

Earlier, intelligence officials said army helicopter gunships killed one person in a car close to Miramshah.