Mobile messaging startup Snapchat has reportedly rejected an acquisition offer from Facebook that would have valued the company at more than $3 billion.

The Wall Street Journal said the all-cash deal would have been Facebook’s largest acquisition ever.

Snapchat, which allows users to exchange smartphone photos and videos that automatically disappear in 10 seconds or less, is popular among teenagers.

The report of Facebook’s interest in Snapchat comes a couple of weeks after the world’s number one internet social network acknowledged that it was seeing a decline in daily use by young teenagers in the US, although it said overall use by teenagers was stable.

The Wall Street Journal said Snapchat’s co-founder Evan Spiegel is being wooed by other investors but is unlikely to consider an acquisition or investment until early next year.

The app was launched in September 2011 and, according to its blog, at least 200 million snaps are shared every day.

Children under 13 are not allowed to create accounts and there have been concerns that the app may encourage “sexting”.

To send a message to someone on Snapchat, users need to know their username and add them to a “My Friends” list.