Shares in Google dropped as much as 5 per cent after the market closed, despite the technology giant reporting a first-quarter rise in profits of 3%.

Profits for the first quarter of 2014 came in at $3.45bn (£2.05bn), but investors are preoccupied by Google’s inability to maintain advertising prices.

A widely watched measure, the average “cost per click”, was down 9 per cent from a year earlier.

Analysts are concerned over Google’s inability to charge users higher prices for mobile ads, a key area as more and more internet users access the web via their smartphones.

The losses in after-hours trading more than erased gains made during yesertday’s trading session, taking it further beneath the peak seen in March.

From a high of $610 per share last month, Google shares are now worth $545.5, down over 10 per cent in a month.

Last week US technology stocks suffered their worst one-day fall since 2011 as investors retreated from the sector following a prolonged run higher.