Ramos-Horta was undergoing emergency surgery following the 7 a.m. attack in Dili, the BBC reported. Maj. Domingos de Camara, an army spokesman, said the president of the southeast Asian nation was injured when two cars drove by his house and began shooting, the British network said.
One of the attackers, identified as renegade soldier Alfredo Reinado, was killed by presidential guards and one guard was reported to have been seriously wounded.
Reinado allegedly had threatened last November to use force against the government and had been indicted in connection with fighting between police and rebel troops in 2006.
There were unconfirmed reports from local media that the house of Prime Minister Xanana Gusmao was attacked as well, but no injuries were reported, the BBC said.
Ramos-Horta was awarded the Nobel Peace Prize jointly with Bishop Carlos Filipe Ximenes Belo in 1996.
Timor-Leste -- formerly referred to as East Timor -- gained independence in 2002.