The British pound continued to weaken Tuesday, with investors displaying last-minute nerves ahead of Scotland's imminent referendum on independence, the outcome of which analysts say is still too close to call.

In early European trade, sterling was 0.3% lower against the U.S. dollar, at $1.6178, not far off the year's low of $1.6052 hit last week, and a punchy 5.3% below 2014's high of $1.71 hit in mid-July.

But Barclays's European head of currency research, Marvin Barth, said investors still aren't taking the possibility of an independent Scotland seriously enough. "With less than a week before the event, we believe markets continue to misprice Thursday's referendum," Mr. Barth wrote in a note, adding that he predicts sterling could still see declines of between 4.4% and 8.0% in the case of a vote in favor of a split.

Other strategists said that beyond Scotland, sterling's declines could be enhanced further this week if the U.S.'s Federal Open Market Committee minutes show a hawkish shift, which would indicate a hike in interest rates sooner than initially expected by the market, in turn boosting the dollar.

On Friday, the dollar logged its longest weekly winning streak in more than 17 years, rising against a broad basket of currencies for nine straight weeks, according to the ICE U.S. Dollar Index.

Since the start of the year, the pound has lost around 2.5% in value against the dollar, despite enjoying a robust rally during the first half of 2014.

Kit Juckes, a macro strategist at Société Générale, however, predicts that it may still have much further to go.

"Bookmakers report up to three times as much money being bet on a "No" in the Scottish referendum as on a "Yes', despite the knife-edge opinion polls," he wrote in a note. "That raises the risk of more downside on a "Yes" than upside on a "No" at the end of the week," he added.

London's FTSE stock index, meanwhile, is trading 0.2% lower on the day, extending Monday's losses, which were in part triggered by weak Chinese industrial production data.

Since the start of the month, when fears surrounding the implications of the referendum started spreading through the market, the U.K.'s index of the top 100 stocks is down nearly 0.5%. The Stoxx Europe 600, which was 0.4% lower on Tuesday, is unchanged on the month.

Beyond the U.K., Russia retained its spot on investors' radar as the ruble dropped more than 1% to yet another all-time low against the dollar, of 38.77 rubles, as the U.S. decision on Friday to join the European Union in expanding sanctions continued to weigh on the currency.

The new measures prevent Western energy firms from providing technology and services--other than financial services--to five Russian energy majors' oil projects in the Arctic, deep offshore fields and shale, the U.S. Treasury Department said Friday.

On Monday, Russia said it would create a multibillion-dollar emergency fund for companies hurt by the sanctions--a sign that the country is girding for a long period of economic isolation.

Moscow's Micex proved resilient in early European trade, clinging to a 0.3% gain, but its dollar-traded counterpart, the RTS Index, fell 0.8%.

In commodities markets, gold gained 0.1% to $1,236.50 a troy ounce while Brent crude declined around the same as much, to $97.80 a barrel.

Write to Josie Cox at josie.cox@wsj.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires

Barclays (NYSE:BCS)
Historical Stock Chart
From Mar 2024 to Apr 2024 Click Here for more Barclays Charts.
Barclays (NYSE:BCS)
Historical Stock Chart
From Apr 2023 to Apr 2024 Click Here for more Barclays Charts.