The prices of graphics cards made by US semiconductor giant Advanced Micro Devices (AMD) soared due to increased demand from cryptocurrency miners, especially litecoin miners.

Graphic cards based on AMD's top-of-the-line R9 290X graphics processing unit (GPU) are now priced at about $900 (£539, €657) due to strong demand. They were launched at a price of $549 four months before.

Meanwhile, prices for cards based on the less powerful R9 290 GPU increased to about $600 from $399 at launch.

Litecoin, like Bitcoin, is a cryptocurrency. It is mined by using GPUs, which are rarely used for bitcoin mining. At present, bitcoins are primarily mined by using application-specific integrated circuits (ASICs), which are customised for particular uses.

The increased demand by litecoin miners has emptied the shelves of AMD's Radeon hardware, which is used to build mining platforms, prompting the company to take advantage of the situation.

The increase in prices has happened despite GPU-based Litecoin mining becoming more difficult due to the ever-increasing number of miners in the field.

AMD GPUs are said to be more efficient in mining litecoins than those built by its rival Nvidia.

Litecoin is inspired by and technically nearly identical to Bitcoin. It confirms transactions faster, every 2.5 minutes, rather than every 10 minutes for Bitcoin.

It currently has a market capitalisation of $414.9m, with 25.7 million coins in circulation at a price of $16.13 per piece, according to