Gunmen kidnapped at least two foreign oil workers from a bus in southern Nigeria Thursday, a day after a U.S. oil worker was killed in the same city, a hub of this country's oil industry.

Two foreign nationals were seized as they rode to work in Port Harcourt, police Commissioner Samuel Adetuyi told The Associated Press. He gave no further details.

In Italy, the Foreign Ministry said an Italian and possibly two more people were kidnapped Thursday in Port Harcourt in what appeared to be the same incident.

It was the second attack in about 24 hours on foreigners in Port Harcourt, where many oil-services companies base their main Nigerian operations.

A gunman riding a motorcycle killed an American riding in a car to work Wednesday at the offices of the U.S. drilling equipment maker Baker Hughes Inc.

Crude oil futures jumped more than $1 a barrel Thursday after the news intensified worries about supply disruptions in Africa's leading oil exporter, the fifth-biggest source of U.S. oil imports.

A militant movement whose attacks on oil installations have cut more than 20 percent of Nigeria's 2.5 million barrel daily production said Tuesday it would target oil workers with fresh attacks.

But a spokesman for the Movement for the Emancipation of the Niger Delta said in an e-mail to The Associated Press Thursday that the group wasn't responsible for either the slaying or the kidnappings.

The group has kidnapped American and other foreign oil workers and released them unharmed.

The Movement for the Emancipation of the Niger Delta claimed that it had information that Thursday's kidnapping stemmed from a "community related dispute" between inhabitants of the Bukuma township and oil companies.

Italy said the kidnapped Italian man works for Saipem, which is 43 percent-owned by the Italian energy company Eni and provides engineering, procurement, project management and construction service for the oil and gas industry, with a specialization in activities in deep water and remote areas.

Eni said it had no details of the kidnapping but was talking to its staff in Nigeria to find out more. Company officials in Nigeria weren't immediately available for comment.