The attack highlights the need for alternative routes.
A conflict could reduce Nigeria's oil output, affecting global oil supply.
Readers write about how the US government can promote green energy, why the BBC should air a commercial requesting aid for Gaza, and how Israel provokes violence from Hamas.
Since 2007, at least 13 journalists have been killed while working on stories and more than 50 have been forced to leave the country, according to the Committee to Protect Journalists and the National Union of Somali Journalists.
The UN evacuated about 300 people Thursday but human rights groups say a humanitarian crisis is looming.
'The Beeb' stands by its decision not to air a fundraising appeal for victims of Israel's recent 22-day incursion into Gaza.