FACTBOX: Uzbekistan presidential candidates

(Reuters) - Uzbekistan votes in a presidential election on Sunday certain to extend Islam Karimov's 18-year rule by a third seven-year term.

Below are key facts on the election procedure and presidential hopefuls. All of them support Karimov and have not publicly criticized his policies, a line-up seen by analysts as a bid to create a semblance of a fair contest.

PROCEDURE

* Uzbekistan has more than 16 million eligible voters.

* Turnout must be more than 33 percent for election to be valid.

* Polls open between 6 a.m. (8 p.m. Saturday EST) and 8 p.m. (10 a.m. Sunday EST).

* If no candidate wins more than 50 percent, a second round between the top two candidates is held within a month.

* Official results have to be published within 10 days.

* The president-elect is inaugurated within two months of the official results being announced.

* The president is elected for 7-year term.

CANDIDATES

ISLAM KARIMOV, 69, incumbent president, nominated by the Liberal Democratic party

Program includes efforts to bring more democracy, reduce the income gap between the rich and the poor and raise living standards while pressing ahead with market-economy reforms.

Also calls for further economic liberalization, a strong civil society, peaceful coexistence with neighboring countries and partners.

In power since 1989, the tough former Communist boss is accused by international human rights groups of violating basic freedoms and blocking democracy.

ASLIDDIN RUSTAMOV, 47, National Democratic party