The fire on the West Pier flared up again on Monday lunchtime
Firefighters have said a fire at Brighton's West Pier, which was probably started deliberately, has flared up again.
The fire - the second to sweep though the structure in less than two months - first broke out in the early hours of Sunday.
It was brought under control within hours but firefighters were forced to leave several "hot spots" burning because they were unable to reach them safely.
The flames re-ignited at 1215 BST on Monday and an East Sussex Fire Brigade crew was sent to monitor the situation.
A spokesman said firefighters were limited in what action they could take because the structure had been declared unsafe.
If I was a betting man, I would bet that this one has been started deliberately
Danny Sherman, Roedean Fire Station
Sussex Police said on Monday they were "remaining open-minded" about the cause of the fire.
Inspector Dick Shelton said: "At the moment we are keeping an open mind about the fire.
"It is too early to say if it is arson, although that clearly is one line of inquiry."
Fire crews were called to the Grade-I listed landmark at 0206 BST on Sunday after reports of flames in the partially-collapsed ballroom.
Danny Sherman, station officer for Roedean Fire Station, said: "There were several seats of fire inside the structure itself - which is very unusual.
'Fireworks in the town'
"If I was a betting man, I would bet that this one has been started deliberately."
"It is contained but the problem is we cannot actually get into the structure to establish where all the pockets of fire are - so we could be here for some time."
The 137-year-old structure, derelict since 1975, was largely stripped to its cast iron shell after a fire on 28 March.
A Sussex Police spokesman said on Sunday there had been reports of fireworks being let off on the seafront in the vicinity of the pier.
He said: "There were some fireworks in the town in connection with the Brighton Festival.
Alarm raised by clubbers
"We don't know whether any of these fireworks were responsible or not.
"They are not sure where the fireworks were at the moment."
Hundreds of people leaving the city's clubs and bars spotted the fire, with scores of calls made to East Sussex Fire Brigade.
It was a similar scene in March when a massive blaze ripped through the pavilion, leaving little but the original steel structure.
The pier's owners believed that fire was started deliberately - but police said last week they had no evidence to prove it was arson.
In December and again in January, large parts of the pier collapsed into the sea.
In February Brighton and Hove City Council voted, despite fierce opposition, to press ahead with ambitious plans to restore the pier at a cost of £30m.