Members of Movement for the Emancipation for the Niger Delta in Nigeria's Niger Delta area (file photo)

The main rebel group in Nigeria's restive, oil producing Niger Delta region has made threats against a planned multi-billion-dollar pipeline project that would deliver natural gas from Nigeria to Europe.

In an email message sent to reporters Saturday, the Movement for the Emancipation of the Niger Delta  (MEND) warned investors that unless  what it called "root causes" in the Niger Delta are addressed and resolved, any money put into the pipeline project would be wasted because it will be sabotaged.

MEND has frequently stolen oil, sabotaged oil installations and kidnapped oil workers for ransom since late 2005.  The group and other militants have been fighting for greater control of natural resources in the region.

On Friday, energy ministers from Nigeria, Algeria and Niger signed an agreement to build the pipeline that would would run from Nigeria, across Niger and Algeria to Europe.   

The European Union says the pipeline could help ease Europe's dependence on supplies from Russia. Officials estimate the Trans-Saharan pipeline would cost at least $13 billion.

The agreement comes just over a week after Russian President Dmitri Medvedev met with Nigerian leader Umaru Yar'Adua.  During the meeting in the Nigerian capital, Abuja, Mr. Medvedev said his country was ready to invest billions of dollars in Nigeria and work toward the Trans-Sahara pipeline.

Some information for this report was provided by AFP.