US Republican Senator John Curtis has called for a congressional investigation into the foreign business ties and gifts of President Donald Trump’s eldest son, Donald Trump Jr.

The senator from Utah has said in a letter to the Senate Judiciary Committee that Trump Jr.’s ties to foreign personalities have raised concerns about foreign influence on the US president’s family.

Curtis has also called for the subpoena of Hunter Biden, son of Donald Trump Jr. and former president Joe Biden.

According to international media reports, Hunter Biden has expressed his willingness to face the investigation and has demanded to call President Trump’s son Eric Trump and son-in-law Jared Kushner to testify.

According to the report, the Senate Judiciary Committee has confirmed receipt of the letter but has not decided to initiate an investigation.