* Deals to strengthen domestic, international routes
* Boeing purchase for 737-800 jets, $724 million cost
* Air Algerie facing rivalries on foreign routes
ALGIERS, Jan 6 (Reuters) - Algeria's national carrier Air Algerie signed deals on Monday to buy three 250-seat Airbus passenger jets and eight 150-seat jets from Boeing , company officials said.
The government-owned airline announced its intention last year to buy 14 passenger aircraft ranging from 70 to 250 seats and two 13-20 tonne-capacity cargo jets, in order to renew its fleet and fend off growing competition.
"This will help us reinforce domestic and international routes," Air Algerie chief Mohamed Salah Boultif said at a signing ceremony in Algiers.
Boultif said the aircraft - Airbus 330-200 passenger jets and Boeing 737-800 jets - would be delivered between next September and the end of 2016 in agreements that would be financed by Algerian state banks.
Boeing in a statement said its deal for eight 737-800 aircraft was worth $724 million at list prices when the order was finalized.
Air Algerie will also sign a deal to purchase another three 70-seat 72-600 aircraft from ATR, a joint venture between Airbus parent EADS and Finmeccanica unit Alenia Aermacchi.
Air Algerie said it was also in talks also to purchase two cargo planes. One Algerian official said the carrier was in negotiations with Boeing over that deal.
Algeria's state carrier has a monopoly on domestic routes, but faces growing competition on external flights, where its main overseas routes are to Europe and the Middle East.
Main rivals include Air France and British Airways, but Qatar Airways, Emirates and Royal Jordanian are among other airlines that have started regular direct services to Algiers.