A police officer and two policemen guarding an outpost near the Iraqi-Syrian border in Iraq \'s western province of Anbar were killed on Wednesday in a clash with gunmen, a source from Anbar province said. Unidentified gunmen attacked the outpost located near the al- Walid border crossing point with Syria and exchanged fire with the Iraqi border guards, killing an officer and two policemen before they fled the scene into the Syrian territories, the source told Xinhua on condition of anonymity. In the mean time, Iraqi security forces captured Adnan Waies, said to be one of al-Qaida leaders in Anbar province, during an operation in the country\'s western desert, where the group militants believed to be holed up, the source said. The capture of Waies, was part of a major military offensive, dubbed \"al-Shabah\" or Fantom in English, aimed at hunting down al- Qaida militants in the vast desert area of the Sunni heartland of Anbar province.