SEOUL -- The deployment of the Terminal High Altitude Area Defense (THAAD) missile defense system in South Korea was delayed to unspecified dates after the country's presidential election ends next month, Yonhap news agency reported Monday.

An unidentified senior South Korean government official was quoted as saying South Korea and the United States shared views that it would be physically impossible to complete the THAAD installation in South Korea before the presidential election.

A presidential by-election is scheduled here for May 9 as former President Park Geun-hye was ousted from office on March 10.

Two mobile launchers and part of THAAD elements were delivered to a US military base in South Korea in early March, boosting expectations for a hurried deployment of the US missile shield before the election.

One THAAD battery is composed of six mobile launchers, 48 interceptors, an AN/TPY-2 radar and a fire & control unit.

Moon Jae-in of the biggest Minjoo Party, a frontrunner in recent opinion polls, have claimed the final decision on whether to deploy THAAD in South Korea should be made by next government after the presidential election.

Seoul's defense ministry spokesman Moon Sang-kyun told a regular press briefing that it would be hard to finish the THAAD deployment in the short term.

Seoul and Washington agreed in July last year to install one THAAD battery in southeast South Korea.

It caused strong oppositions from regional countries, including China and Russia, as it breaks strategic balance in the region and damages security interests of these countries.