Police are seeing some gang members "move across" to using acid or corrosive fluids in attacks, a senior officer has said.

Metropolitan Police Deputy Commissioner Craig Mackey said officers were looking at potential links between London gangs and a recent spike in acid attacks but cautioned that the evidence was limited.

MPs this week debated possible measures to counter the crimes, including tougher sentences, and the Government has proposed classifying corrosive substances as dangerous weapons.

Mr Mackey told the London Assembly Police and Crime Committee there were 455 acid offences recorded in London last year, with 63% being assaults.

He said 23% were related to robberies and the rest were criminal damage, while the majority of victims were aged between 15 and 29 and nearly a third were Asian.

"About 80% of the victims and about 82% of the suspects are male so it's a predominantly male-pattern behaviour," Mr Mackey said.

"East London is a hotspot ... although there are offences across London.

"We are seeing some links - although it has to be treated with caution because it's a small data set - a growing feature between named suspects in acid attacks who also feature in our gang matrix.

"So please don't read that as gangs have all moved lock, stock and barrel into acid, but we are seeing a move across.

"We have hypotheses for this, we have tests that we think, 'is it something around a focus on knives and knife crime sentencing', but there is no evidence to support this yet. It's just something that we are looking at."

His comments come after the Met arrested four teenagers, two aged 17 and two aged 18, for possession of a suspected corrosive substance following a stop and search in Leytonstone at around 8.50pm on Wednesday.

A bottle of suspected corrosive substance, gloves and a balaclava were recovered from the car the suspects were travelling in.

Last week five separate male victims - all on mopeds and including a fast-food delivery driver - were allegedly targeted by two moped-riding attackers in north and east London.

Mr Mackey said: "Officers are out there - I saw on the logs last night where they had arrested someone carrying a bottle with acid in.

"So they are out there doing it day in, day out. We are intervening, stopping, searching people, seizing stuff and making arrests."

The Met chief supported moves in Parliament to tackle the issue, saying some of the substances are "not even defined by law".

He added: "The impact this sort of attack has on people is extraordinary.

"Many of us have been unfortunate to see quite a bit in our services but acid attacks are really extraordinary and strike at something quite horrific in people's psyche."