KHARTOUM - Sudan has rejected a US request to send a platoon of Marines to bolster security at the US embassy in Khartoum, the state news agency SUNA said on Saturday.On Friday, a US official told Reuters that Washington would send Marines to Sudan to improve security at the embassy after protesters entered the mission in a demonstration against a film that insults the Prophet Mohammad."Sudan is able to protect the diplomatic missions in Khartoum and the state is committed to protecting its guests in the diplomatic corps," Foreign Minister Ali Ahmed Karti told SUNA.