Allegations of U.S. involvement in an coup plot in Sudan are being denied by both the U.S. Government and the Khartoum government. The allegations were made by a Sudanese Presidential assistant, who accused the United States of backing a plot to assassinate members of President Omar al-Bashir's government. A U.S. embassy statement categorically denied any connection with what it called the "alleged conspiracy." As Nick Wadhams reports from our East Africa bureau, Sudan's government has also rejected the allegations of U.S. involvement, but has detained several people on charges of plotting a coup.

Sudanese authorities arrested 14 people Saturday, including the leader of the opposition Umma Reform and Renewal Party, on charges that they were smuggling weapons into the capital Khartoum in preparation for a coup. Retired army officers and a former tourism minister were also detained.

The government says the plotters wanted to create enough unrest in Sudan to compel intervention by the international community. It says officials from Libya exposed the plot after one of the chief conspirators, Mubarak al-Fadil, turned to it for financial help.

The Paris-based Sudan Tribune Web site reported that presidential adviser Nafi Ali Nafi had told the al-Jazeera news channel that Washington was behind the plot.

But Foreign Ministry spokesman Ali Sadiq Ali said no such allegation was made.

"It is not correct," said Sadiq. "Mr. Nafi did not mention any country by name, so it is not true that Mr. Nafi has mentioned the United States. The investigations now are going ahead with those people and I do not think any name will be disclosed. To the best of my knowledge as spokesman of the Foreign Ministry I have no idea that the government of Sudan has mentioned any particular country in this issue."

The alleged leader of the coup plot, Mubarak al-Fadil, had recently moved his party away from its initial pro-government stance and had sought to reunite with an opposition group that it had broken with in 2002. He had been a presidential adviser, but was fired in 2004 after purportedly making contacts with the United States without Sudanese leader Omar al-Bashir's consent.

The government was also said to be angered by recent comments in which Fadil criticized the government's handling of the Darfur crisis.

Mr. Bashir, who came to power in a 1989 bloodless coup, wields virtually all political power in his nation and has repeatedly accused his opponents of planning to overthrow him. In 2005, 28 people were arrested on allegations of a coup plot.

On Friday, U.S. envoy to Sudan, Andrew Natsios, said Sudan has resumed bombings against civilians in its western Darfur region. He said Arabs have begun to occupy lands in Darfur that were previously occupied by non-Arabs.