Fire service warning over deliberate grass fires
Fire service leaders say they are targeting people who start grass fires after hundreds of calls this week.
One hotspot in the Cynon Valley saw crews called out over 20 times in four days to deal with fires, many of which are thought to have been deliberate.
Police patrols are being increased and CCTV is being used to catch offenders.
Firefighters have been busy across Wales, with one mountain blaze near Llangollen, Denbighshire, burning for many hours and covering 150sq m.
South Wales Fire Service said it had been called out to 270 grass fires in the past week and almost 600 over the month.
More than 100 fires this week have been in Rhondda Cynon Taf alone, while only two have been reported in both the Vale of Glamorgan and Monmouthshire.
One of the worst-hit areas has been around Perthcelyn in Mountain Ash, Cynon Valley.
The fires are said to have had "a significant impact" on the resources of the fire service because "crews are committed for many hours".
Jason Evans, station manger for Aberdare, said the fire service was working with the police and other partners "to ensure that deliberate fire setters, that cause wilful damage to property and endanger the lives of members of the public and firefighters, are apprehended and brought to justice".
He added: "Anyone thinking about deliberately setting fire to the mountainside needs to realise that we will pull out all the stops to ensure that they are caught and could face prosecution."
Firefighters have been tackling grass and mountain blazes across Wales this week.
North Wales fire service said it had attended more than 20 incidents involving grass and gorse fires since Tuesday, and been notified of more than 70 incidents "where farmers were carrying out controlled burning".
The largest gorse fires were said to have been in Caernarfon in Gwynedd, Llanrwst in Conwy, Conwy itself and Corwen, Denbighshire.
Mid and West Wales crews tackled four separate fires in one hour in the Swansea and Cymer areas alone on Wednesday evening.
The number of deliberate fires has been generally falling in Wales since 2003 but three-quarters of the most serious grass fires are thought to be set on purpose.
Recent figures suggested nearly four out of 10 of the most serious blazes were started by people with matches.