Port Harcourt (Agencies): A stampede at a campaign rally on Saturday for Nigerian President Goodluck Jonathan in the oil-producing Niger Delta region killed about 11 people and hut 29 others, police said.

The incident took place in the oil city of Port Harcourt after Jonathan addressed the crowd, according to witnesses. A witness said a police officer shot into the air as crowd members surged out of the 20,000-seat stadium.

While the gunshots were clearly aimed at controlling the crowd, they instead created panic, with the main gate appearing locked and rally-goers trying to leave through a narrow passageway.

A number of people were trampled in the rush, witnesses said, and other exits to the stadium seemed to be locked with Jonathan still on the premises.

"The mishap was said to have been caused by a stampede as a result of a surging crowd which led to the death of 11 persons and causing injuries to about 29 others," police informed.

"I am sad, and heavily weighed down by this incident. It is sad, unfortunate and regrettable," Jonathan, who is the first President from the Niger Delta region in the country's south, stated.

The President directed a probe into the cause of the frenzied rush "that led to the unfortunate loss of some lives."

Chris Amadi, a ruling Peoples Democratic Party (PDP) member from Rivers State, where Port Harcourt is the capital, said he saw above 10 people trampled over by the mammoth crowd.