Washington (CNN) The Senate Intelligence Committee has subpoenaed Donald Trump Jr. for him to return and testify again, and the committee is now at a standoff with President Donald Trump's eldest son, according to sources familiar with the matter.

One option Trump Jr. is considering in response to the subpoena is to invoke his Fifth Amendment rights, and another is just to not appear at all, according to one source. The subpoena from the Republican-led Senate Intelligence panel is believed to be the first issued to one of Trump's family members.

Discussions for Trump Jr.'s testimony began several weeks ago before special counsel Robert Mueller's report was released, the sources say. Trump Jr.'s team resisted giving testimony, in part, because the findings of the Mueller report were still not known.

During the negotiations, the idea to use written questions and answers was floated, and at another time it was proposed that Trump Jr. sit for an untranscribed interview, according to one source.

The subpoena was issued more than two weeks ago, according to a source familiar with the matter, and it compelled Trump Jr. to testify before the committee, the source said.