February 2016

Jeff Sessions is the first Senator to endorse Mr Donald Trump for president.

March 2016

Mr Trump announces Mr Sessions will lead his national security advisory committee.

June 2016

Democratic National Committee (DNC) says Russian hackers penetrated its computers, gaining access to internal emails.

July 2016

Republican National Committee (RNC) officially nominates Mr Trump for president at its convention in Cleveland. His team gets the RNC to change anti-Russia language in the party platform. WikiLeaks begins releasing stolen DNC emails. FBI investigates. Intelligence officials tell the White House they have "high confidence" that Russia is behind the DNC breach.

September 2016

President Barack Obama meets with Russian President Vladimir Putin at G20 meeting in China, and said tells him "to cut it out," and "there were going to be serious consequences if he did not." Mr Sessions meets with Russian ambassador Sergey Kislyak in his Senate office.

October 2016

Department of Homeland Security releases assessment saying leaked emails "are intended to interfere with the US election process". In second presidential debate, Mr Trump says: "They always blame Russia, and the reason they blame Russia is because they think they are trying to tarnish me with Russia."

November 2016

Mr Trump wins the election.

December 2016

US intelligence agencies conclude that Russia was behind DNC hack in order to improve Mr Trump's chances in the election. Mr Obama announces fresh round of sanctions against Russia, asks 35 of its diplomats to leave the US.

Mr Michael Flynn, Mr Trump's nominee for national security adviser, speaks with Mr Kislyak on the phone, reportedly to discuss easing sanctions on Russia during the Trump administration.

Russian President Vladimir Putin does not retaliate against the US. Mr Trump tweets "Great move on delay (by V. Putin) - I always knew he was very smart!"

January 2017

Mr Trump sworn in as president. Nominated Mr Sessions for attorney-general. In his confirmation hearings, Mr Sessions tells Senators he had no contact with anyone from the Russian government during the election.

February 2017

Mr Sessions is confirmed and sworn in as Attorney General. Mr Flynn resigns as national security adviser after reports that he misled Vice President Mike Pence about conversations with Mr Kislyak.

March 2, 2017

The Washington Post reports that Mr Sessions met twice with Mr Kislyak. Mr Sessions denies that his conversations with Russian officials were related to the presidential campaign, but recuses himself from investigations.

Sources : NYTIMES, Centre for American Progress Action Fund