Oil prices fell on Monday, despite the US dollar's slip, weighed down by growing concerns about the Omicron variant.

Several European countries, such as the UK, started to see record daily spike in Covid-19 infections due to the Omicron outbreak, which threatens another lockdown and closures.

Countries such as Denmark, Norway and Austria have also tightened restrictions on citizens, especially on the unvaccinated.

The American biotech frim Moderna reported that a booster shot of its vaccine protect from Omicron infection.

The World Health Organization said that Omicron cases appeared in more than 90 countries, with over 1000 cases in 43 US states so far.

The dollar index fell against a basket of major currencies by 0.1% to 96.4 points as of 18:45 GMT, after hitting a high of 96.6 points and a low of 96.3 points.

WTI January futures fell 4.1% to $67.9 a barrel, as of 18:43 GMT.

Brent February futures fell 3.5% to $70.9 a barrel.