GLASGOW (AFP) - Rangers moved seven points clear of Celtic in the Scottish Premier League on Saturday but manager Walter Smith is still seeking to strengthen his squad by the end of the month.

A 4-0 home victory over 10-man St Mirren stretched the Ibrox club's lead over their Old Firm rivals ahead of the champions match at Falkirk on Sunday.

"I'll feel a lot better if we still have a seven-point advantage on Monday but that depends on results elsewhere," said Smith.

"I'm just delighted we have managed to win our game against St Mirren as I knew it would be a difficult match."

The Rangers boss continued: "We're actively looking for players who can improve the team and I've said that since the start of the transfer window. We'd like to bring in players in quite a number of positions and we'll endeavour to try and get them but it's a tough task."

With Rangers expected to lose Northern Ireland goalkeeper Roy Carroll to Derby before the January transfer window closes at midnight on Thursday, they are looking to bring in back-up for first choice goalkeeper Allan McGregor.

Before Saturday's match, assistant manager Ally McCoist told BBC Radio Scotland they were in the process of trying to sign Dundee United's out of contract Polish keeper Grzegorz Szamotulski.

He said: "Szamotulski is someone we've been looking at for a while and we're definitely interested in him but I'm not too sure how far down the line Walter is with that."

Smith was more cagey but admitted: "We're in the process of trying to sign a goalkeeper but we've been trying to sign one for the past 10 weeks and have been thwarted on a number of occasions."

Although Rangers finished as comfortable 4-0 victors on Saturday the sending-off of St Mirren's Will Haining in the 37th minute changed the complexion of the match.

The Paisley side had started the match brightly and although Chris Burke had put the hosts ahead in the 27th minute the Saints were very much in the game until referee Mike Tumilty showed Haining a second yellow card in the 30th minute for a late challenge on Alan Hutton.

St Mirren manager Gus MacPherson believed the first booking - for a tackle on Rangers striker Jean Claude Darcheville - was harsh on his player.

He said: "If Darcheville had got up a bit quicker the booking wouldn't have happened. Rangers actually tried to take the free-kick quickly and if they had been allowed to Haining would not have been booked.

"Instead, because the player received treatment the referee decided to book Haining. There had not been a challenge up until that point so I don't think a yellow card was merited."

After the sending-off Kris Boyd doubled his side's advantage in the 33rd minute and Steven Whittaker made it 3-0 four minutes later. Whittaker completed the scoring in the 81st minute with a curling shot into the top corner from 20 yards.