The United States, Sweden and Italy have responded to Bulgaria's request for proposals for supply of up to 16 fighter jets, the defence ministry in Sofia said on Monday. The US has offered to supply new F-16 or F-18 jets, Sweden - new Gripen fighters, while Italy has offered used Eurofighter aircraft, the defence ministry said in a statement. A working group appointed by the prime minister is expected to complete assessment of the offers by October 19, although the deadline may be extended. Upon completion of the assessment, a second working group also appointed by the prime minister will hold talks with the bidders for improving the terms of the offers, the ministry said. In July, Bulgaria sent requests for proposals for supply of up to 16 new or used multipurpose fighter aircraft to seven countries - the US, Portugal, France, Germany, Israel, Italy and Sweden. Bulgaria sought offers for supply of new or used F-16 and F/A-18 Super Hornet jets from the United States, new or used Dassault Rafale from France, Gripen C/D from Sweden, new Eurofighter 3 Tranche jets from Germany, used Eurofighter Tranche 1 fighter jets from Italy and used F-16 from Portugal and Israel.