America's Daniel Berger and Russell Henley are locked in a four-way tussle for the lead at the midway point of the Travelers Championship on home soil in Cromwell.

Tyrone van Aswegen and Marc Leishman, who shot rounds of four-under-par 66 and two-under respectively, are also in the race for the title as they hold a share of the lead after round two.

Van Aswegen has never previously tasted victory on the PGA Tour, but he carded four birdies on Friday and did not drop a single shot to remain in the hunt.

Englishman Russell Knox is further back in a tie for second, while compatriot Paul Casey - who shot 67 to go with his first-round 68 - is level with former world number one Vijay Singh as one of six players at five-under-par overall.

Bubba Watson is four shots off the pace, meanwhile, having decided to defend his title here rather than compete in the Olympic Games.