So far 41 people have been arrested on suspicion of drugs and other offences at Manchester's Parklife music festival.
Some 25 were arrested on Saturday and by 8pm on Sunday 16 more had been arrested, a spokesman for Greater Manchester Police confirmed.
Although two warnings have been issued about high-strength ecstasy circulating at the event in Heaton Park, there have been no reports of anyone falling seriously ill.
A spokesman for GMP confirmed that so far on Sunday 16 people had been arrested on suspicion of possession of drugs, theft and handling stolen goods.
One person was arrested over an alleged assault.
On Saturday, there was also one reported assault.
At last year's event, some 56 people were arrested, mostly for drugs offences.
Drug-testing organisation The Loop, which has a team of people on site, has so far issued two warnings, one concerning orange and white 'Sprite' pills said to be three times stronger than average.
Posting an image of the pills on Twitter on Saturday night, the charity described them as 'solid, tough pills with NL stamp and break line on back'.
The Sprite pills are said to contain 300mg of MDMA per tablet.
Anyone feeling unwell was urged to seek urgent medical help.
Yesterday The Loop also warned of high strength purple and pink 'skype' ecstasy pills which had been tested at Parklife and 'linked to welfare cases'.
More than 80,000 people attend each day of the festival.
Parklife boss Sacha Lord issued a drugs warning ahead of the festival and urged all those at Parklife to look after each other.
Writing on social media this morning, Mr Lord urged festival-goers to 'Have a good one, pace yourselves, look after each other'.
