Cambodia's opposition party has condemned political "intimidation" ahead of the country's elections, after a gun shot was fired into the party's headquarters early on Saturday.
Yem Ponharith, a spokesman for Cambodia's National Rescue Party (CNRP), has told Radio Australia a glass window was hit by the gun shot but no one was injured.
Opposition leader Sam Rainsy has denounced the attack as an attempt by people in power to intimidate the opposition ahead of general elections on July 28.
"I condemn all intimidation," Mr Rainsy said.
CNRP spokesman Yim Sovann says the attack is a politically motivated case.
"This is a cowardly act," Mr Sovann said.
"We're not scared by this attack at all."
National police spokesman Kirt Chantharith confirmed the attack by an unidentified gunman and said police had collected a bullet.
"We are investigating the case," Mr Chantharith said.
The attack comes 24 hours after opposition leader Sam Rainsy's return to Cambodia from exile in France.
Another shot was fired last week at members of the opposition during a rally in Phnom Penh.