KANDAHAR, Afghanistan (AP) — Three Italian medical workers are among nine people who were detained in an alleged plot to kill an Afghan provincial governor, officials said Saturday.

They were detained after suicide bomb vests, hand grenades, pistols and explosives were discovered in a hospital storeroom in Lashkar Gah, the capital of the southern province of Helmand, a spokesman for the provincial government said.

Police were tipped off about a plot to kill Helmand's governor during a future visit to the hospital, spokesman Daud Ahmadi said Saturday.

A video of the raid obtained by Associated Press Television News shows British troops accompanying Afghan police, soldiers and government officials to the city's Emergency Surgery Center for Civilian War Victims, run by the Italian private group Emergency.

In a storeroom, boxes are opened containing what appear to be bullets, pistols, hand grenades, and bags of explosives. A British soldier is heard saying that an explosives disposal unit was on its way.

Three foreign staff members are then shown sitting on outdoor benches, their identification cards visible but names unclear.

In a statement, the Milan-based organization denied involvement in any plot and said it was confident its staffers would be exonerated. It said it had not been allowed telephone contact with the three suspects and that the Afghan government and international forces had not explained why they were being held.

"These are people who for years worked to ensure care for the people of Afghanistan. We ask that you respect their rights, first of all, the right to communicate with us and let us know where they are and what their condition is," the statement said.

Calls to the Italian Embassy in Kabul rang unanswered Saturday. A NATO spokesman in Kabul said its forces had not taken part in any arrests.

Helmand's governor, Gulab Mangul, confirmed the arrests at a news conference, saying those held included three Italians and six Afghans.

His spokesman, Ahmadi, said that upon questioning, the hospital storeroom's supervisor implicated others, eventually leading investigators to the Italians. There was no immediate indication of whether any other evidence implicated the three, and their names were not immediately available.

Ahmadi said the six Afghans worked at the hospital as clerks, guards or translators.

Investigators believe the nine were linked to the Taliban insurgency and that the plan had been hatched at a meeting in the Pakistan city of Quetta, Ahmadi said.

He said the plotters planned to carry out a suicide bombing in Lashkar Gah, then wait until the governor came to the hospital to visit the injured. When he did, they planned to attack with grenades, pistols and explosives, Ahmadi said. No other details were available.

Taliban are active in the province, where international forces in February began a major offensive against the insurgency.

Emergency has had a tense relationship with local authorities, due in part to its policy of treating all patients, including those who may be Taliban.

It has operated in Afghanistan since 1999 and currently runs three surgical centers, a maternity center and a network of 28 health centers.

Copyright 2010 The Associated Press.