2003 Fiat Palio Temperature Indicator Rising when A/C on

HI All,
When i switch on the A/C the temperature level goes to the RedMark level after driving for 3 kms. I have checked the Fan its working proper. Refilled the A/C gas. When the A/c is off there is no problem with the temperature ridsing

Any help to diagnose the problem please

Thanks in Advance
thomson