Former National Security Adviser Michael Flynn has invoked his Fifth Amendment protection against self-incrimination and won't comply with a Senate subpoena requesting documents related to his communications with Russian officials.

The decision comes nearly two weeks after the Senate Intelligence Committee issued the subpoena as part of the panel's investigation into Russian meddling in the 2016 election. Legal experts had previously noted that Mr Flynn wasn't likely to comply with subpoena requests unless he was granted immunity because doing so would be giving up constitutional protections. Mr Flynn had also requested immunity from "unfair prosecution" previously when asked to comply with the committee's investigation.

A letter written for Mr Flynn by his legal team said a daily "escalating public frenzy against him" and the recent appointment of a special counsel have created a dangerous legal area for Mr Flynn, according to the Associated Press.

Mr Flynn was forced to step down from his post in the White House in February after it was discovered that he had misled Vice President Mike Pence regarding conversations he had with a Russian official during the presidential transition period. He had wrongly informed Mr Pence that he had not discussed US sanctions on Russia that were imposed as punishment for meddling in the 2016 election.

Since his resignation, several details have emerged. Sally Yates, then the acting attorney general, warned the Trump administration that Mr Flynn could be compromised because of his misleading conversations nearly three weeks before the resignation. Mr Flynn had also received tens of thousands of dollars in payments from Russian sources that he did not disclose or receive approval for, which is required since he is a retired lieutenant general.

Mr Flynn is one of several former Trump campaign officials who have been asked to provide documents to congressional investigations related to Russian contacts with the Trump campaign. The others include former foreign policy adviser Carter Page, former campaign Chairman Paul Manafort, and informal adviser Roger Stone. Mr Manafort and Mr Stone have both reportedly provided documents to the Senate committee.