The Nigerian government has destroyed an $11m (£7m) stockpile of confiscated elephant tusks that had been smuggled from various African countries.

Environment Minister Iziaq Salako told an event in Abuja that he wanted to send a clear message that the illegal wildlife trade would not be tolerated.

Experts say tens of thousands of elephants are killed worldwide each year for their tusks.

That is despite a decades-long ban on the international trade of ivory.

The haul of elephant tusks destroyed on Tuesday was one of the biggest ever seized in Nigeria, weighing almost 2.5 tonnes. Some had been carved into artworks ready for sale.

The destroyed ivory will now be pulverised into a powder, the environment minister said, which will be used to build a monument symbolising the importance of elephants and Nigeria's determination to protect them.

According to conservationists, Nigeria has become a major hub for the illegal trade in animal parts from Africa. The biggest markets are said to be in Asia.

In October, nearly four tonnes of seized pangolin scales were publicly destroyed.

A recent report estimates that there are fewer than 500,000 elephants in Africa compared to more than 1.3 million in the 1970s. As few as 400 remain in Nigeria.

In some cases, elephants are killed when they come into contact with humans or destroy crops.

In December, Nigerian officials began investigating following outcry at a viral video that showed soldier shooting two elephants that had wandered on to farmland.