A man shot and killed his son with a homemade gun during a birthday party he threw for his father, police said on Tuesday.

The 63-year-old shooter was detained without a warrant after the police were alerted to a shooting at an apartment in Incheon, west of Seoul.

The man is suspected of firing two shots at his son in his 30s during the party, which was also attended by his daughter-in-law, his two grandchildren and friends, police said.

The motive behind the suspect?s shooting was not known.

The gun was in pipe-form and the bullets hit the son?s chest, he was moved to a hospital but was later pronounced dead.

The Seoul Metropolitan Police Agency said a special unit team discovered 15 explosive devices at the suspect?s home and safely dismantled and removed them.

One device was connected to an ignition by a plastic bottle containing flammable liquid and was set to go off.

In addition to the two homemade guns he used to shoot his son, nine other guns were discovered in the suspect?s car, while five to six metal pipes were found at his home.

Police said they searched the home in Seoul?s northern district of Dobong after the suspect told investigators he had installed an explosive device there.

Authorities promptly evacuated 105 residents from the building before conducting the search. (Yonhap/NAN)

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