ABC

This is the second time the same Russian vessel has come within close proximity of a US Navy ship this month.

On June 17, the Yaroslav Mudryy came within 288 metres of the USS Gravely, an incident US officials called "unsafe and unprofessional", but which the Russian Defence Ministry disputed.

Recent months have seen a number of similar Cold War-style incidents at sea and in the air, with each country's military accusing the other of dangerous approaches in international waters and airspace.

ABC, CBS and NBC have devoted 504 minutes to campaign news on their evening newscasts through last Friday, according to an analysis by the Tyndall Report, which studies the content of these programs. The previous high of 462 minutes at this point came in 2007, another year when no incumbent was running. Tyndall made no such measurements prior to the 1992 campaign.