KIEV (AFP) - Ukraine's President Viktor Yanukovych blasted mass protests against his rule as "extremism" on Monday, Feb 3, 2014, as the European Union and United States mull economic aid to help end the country's political crisis.

In a boost to the opposition, due to press fresh demands in a Parliament session on Tuesday, the EU and US linked any possible economic aid to democratic reforms and a new government.

EU foreign policy chief Catherine Ashton returns to Kiev on Tuesday in a fresh bid to end the two-month standoff, triggered when Ukraine walked away from a political and trade deal with the EU in favour of closer ties with Soviet-era master Moscow.

US Assistant Secretary of State Victoria Nuland is also due to visit Ukraine this week to keep pressure on Mr Yanukovych.

Returning to work after four days of sick leave, President Viktor Yanukovych slammed the anti-government movement as "radicalism and incitement to hatred behind which there is a struggle for power".

He also appeared to link militants to Nazis, calling for "a community of wholesome people without the Nazism, racism and xenophobia that remind us of the terrible lessons of history" in his first public comments since Thursday.

The mass protests have set off sparks between Russia and the West and claimed the lives of at least two protesters and two policemen.

Thousands remain camped out on Kiev's Independence Square and in occupied buildings in the capital.

Ms Ashton's spokesman Maja Kocijancic said the EU and its foreign partners were talking about "what we can do to help support the Ukrainian economy" but stressed any aid would be linked to political reforms or the naming of a new government.

US State Department spokesman Jen Psaki said the talks were "at a very preliminary stage".

"We are consulting with the EU... and other partners about the support Ukraine may need after a new technical government is formed as the country gets back on the path to economic health through the IMF," she said.

Asked to comment, Foreign Minister Leonid Kozhara said in Kiev: "Nobody has discussed this with me."

Opposition leader Arseniy Yatsenyuk has asked for a "Marshall Plan" - a reference to US aid for Europe after World War II - and said the minimum required was the US$15 billion (S$19.1 billion) that Russia has promised Ukraine in a bailout that is now on hold.

But EU diplomats played down the prospect of big funds.

"It'll be difficult to offer as much as the Russians," said one diplomat, speaking on condition of anonymity.

Ukraine's recession-hit economy is hugely dependent on Russia, and Moscow tightened the screws further on Monday by reminding Ukraine it owed US$3.3 billion for supplies in 2013 and so far in 2014.

Even as it ups the pressure, Russia has accused the West of interference in the internal affairs of its former Soviet satellite, and has dismissed the protesters as extremists.

But the opposition says the authorities are the ones using heavy-handed tactics and says there is a "secret repression" in which activists are seized and beaten by pro-government vigilantes.

The case of Dmytro Bulatov, a protester who said he was kidnapped and tortured, is a particularly shocking example of these claims of abuse.

In a statement on Monday from the hospital in Vilnius where he is being treated, the 35-year-old father of three vowed to "keep fighting" for democracy - after EU and US officials expressed shock over his treatment.

Ukrainian activists are also increasingly turning their sights on foreign assets allegedly bought by officials using corruption money and are hoping for EU and US financial sanctions.

Campaigners from the Democratic Alliance party held a protest outside Deutsche Bank's offices in Kiev, asking the German lender to stop working with officials they accused of being corrupt.

They laid out blood-covered banknotes spelling out Mr Yanukovych's name in the snow in protest.

"The point of being in power in Ukraine for them is the corruption. They steal money from the budget and they put it in Europe," said one protester Viktor Andrusiv.

No fresh negotiations are scheduled between Mr Yanukovych and the opposition, which has asked for "international mediation" in the talks.

Mr Yanukovych has scrapped draconian anti-protest laws and the prime minister and the entire Cabinet have resigned under opposition pressure.

But the list of unanswered opposition demands still includes Mr Yanukovych's resignation before the end of his mandate in 2015 and early elections.

An Internet survey by the TNS agency in Kiev found that a majority were in favour of early presidential and parliamentary elections.

But it also showed up rifts in Ukrainian society.

Asked if the protests should continue, 48 per cent said yes and 45.1 per cent said no.