Ross County sign Jason Naismith for fee and Jim O'Brien on loan

Naismith has made over a century of appearances for St Mirren

Ross County have signed St Mirren full-back Jason Naismith for an undisclosed fee, while Shrewsbury Town winger Jim O'Brien has joined County on loan.

Naismith, 22, had agreed a pre-contract to join County in the summer but will move to Dingwall in the current transfer window instead.

O'Brien, 29, previously played in Scotland with Celtic, Dundee United and Motherwell.

Both deals are subject to clearance, with O'Brien loaned until the summer.

County host Dundee United in the Scottish Cup on Saturday and the Highlanders resume their Premiership campaign away to Kilmarnock on 28 January.

O'Brien last played in Scotland with Motherwell in 2010

Defender Naismith came through the Buddies' youth ranks and made his debut in 2012. Capped up to Scotland Under-21 level, he has made more than 100 senior club appearances.

Former Republic of Ireland Under-21 player O'Brien has over 300 club appearances and joined Shrewsbury from Coventry in June.

"We've been tracking Jason's progress for a while now and I'm delighted to secure his services on a permanent deal," manager Jim McIntyre told the County website.

"He is an exciting young prospect and will be a great addition to the squad."

And, of O'Brien, he added: "He will bring competition in wide areas for us and, at 29-years-of-age, he brings a wealth of experience with him."