Washington, July 4 (IANS): The US has slapped sanctions on a man involved in the killing of an American diplomat in the Sudanese capital of Khartoum in 2008.

The State Department added to its blacklist Abd Al-Ra'Ouf Abu Zaid Mohamed Hamza under an executive order targeting terrorists and those providing support for terrorists or acts of terrorism, Xinhua reported.

The move bars US citizens from doing business with him and freezes all of his assets under US jurisdiction.

Hamza, and three others, took part in an armed attack in Khartoum Jan 1, 2008, resulting in the deaths of a US diplomat serving with the US Agency for International Development (USAID) and a local employee at the US embassy, the State Department said in a statement.

The four men were convicted of murder and sentenced to death in a Sudanese criminal court in 2009, but they escaped from a maximum security prison the following year, killing a Sudanese police officer and wounding another in the process, the report said.

Hamza was recaptured soon and is currently in a prison in Khartoum, while another fugitive was reportedly killed in Somalia in 2011.

The other two who remain fugitives at large, Abdelbasit Alhaj Alhasan Haj Hamad and Mohamed Makawi Ibrahim Mohamed, were named by the State Department as specially designated global terrorists in January this year.

The department has offered rewards of up to $5 million each for information leading to the capture of the pair.