Protesters blocked facilities belonging to oil giant Shell on Thursday in Nigeria demanding improvements to communities in the area, including new roads and stable electricity supply.

About 40 protesters accused Shell of breaching a 1999 accord on the provision of electricity and roads for the Oruma, Otuasega, Elebele and Imiringi communities in Bayelsa, home state ofPresident Goodluck Jonathan.

For more than six hours, protesters prevented entry into the Kolo Creek logistics base of Shell and a crude oil delivery line to Port Harcourt, Nigeria's main oil hub, witnesses said.

Their spokesman, Ranami Afagha, said the communities had written several letters and held meetings over the implementation of the accord, which they said was signed in the presence of Jonathan, then Bayelsa deputy governor.

"Shell had agreed then to connect our communities to the plant supplying electricity to their office facility here in our environment but reneged," he told journalists.

"We want our communities to be connected to the source of power that supplies them electricity 24 hours every day."

Reacting to plans for the protest earlier this week, a Shell spokesman said the "Kolo Creek field logistics base has been supplying electricity to Elebele, Imiringi and Otuasega communities in line with an agreement reached in 1999.

"However, these communities have since expanded and the demand for power has exceeded the installed capacity," said Precious Okolobo.

In a statement Thursday, Okolobo reiterated his earlier reaction, adding "we are in the process of engaging the protesting youths who have tampered with our installations in such a manner that poses serious threat to people and the environment.

"The Bayelsa state government has been informed of the situation, and we hope that it will be resolved peacefully," he said.

The Anglo-Dutch firm also said a total of 3.5 million dollars had been disbursed for projects in the protesting communities between 2006 and 2010.

Nigeria is Africa's largest oil producer, but the main oil region, theNiger Delta, where Bayelsa state is located, remains deeply impoverished.