The White House said on Monday violence by the Ukrainian government against protesters was unacceptable and urged authorities to respect Ukrainians' rights to freedom of expression and assembly.
"The violence by government authorities against peaceful demonstrators in Kyiv on Saturday morning was unacceptable," White House spokesman Jay Carney told reporters at a briefing.
Reports of journalists and members of the media being assaulted and targeted by security forces are "disturbing," Carney said.
Meanwhile, Ukrainian President Viktor Yanukovich is planning to head to China on Tuesday looking for loans and investment, despite the massive protests unleashed by his decision not to sign a trade pact with the European Union.
Protesters blockaded the main government building in Kyiv on Monday and brought traffic to a halt, seeking to force Yanukovich from office, after hundreds of thousands demonstrated on Sunday against his decision to turn away from the EU towards Russia. Ukraine's currency and bonds came under pressure, along with share prices.
But the tug-of-war between Brussels and Moscow for influence in Ukraine has so far done little to alleviate its looming debt crisis, and Yanukovich confirmed on state television on Monday that the visit would go ahead.
"Yanukovich is trying to show that the European Union and Russia are not the only possible partners for Ukraine," said Volodymyr Fesenko of Ukraine's Penta think-tank.
However, he said Beijing may now demand assurances over Ukraine's political and economic stability, adding: "Ukraine is unlikely to secure direct financial aid (from China)."
Bad time to go
Beijing has already provided the former Soviet republic with loans worth $10 billion US, but the government must find more than $17 billion in 2014 to meet gas bills and debt repayments.
Including the private sector, Ukraine must make debt repayments of more than $60 billion next year, equivalent to a third of its gross domestic product.
Opposition leaders called on Sunday for Yanukovich and his government to resign. A pro-Europe rally of about 350,000 people, marred by clashes between protesters and riot police, was the biggest protest in the capital Kyiv since the "Orange Revolution" of nine years ago.
"It is a very bad time to go abroad. The president's absence may make talks with the opposition much more difficult," said another Ukrainian political analyst, Gleb Vyshlinsky.
Russia wants to draw Ukraine into a Moscow-led customs union and prevent it drawing closer to the EU, a move that would signal a historic shift towards the West and away from Kyiv's former Soviet masters in Moscow.
Ukrainian Prime Minister Mykola Azarov, who backs closer economic ties with Russia, said at least 20 economic and trade agreements should be signed during the visit to China, including a treaty on friendship and co-operation.
Ukraine had a $15-billion standby agreement with the International Monetary Fund, but this was frozen in 2011 over Kyiv's refusal to end subsidies and raise household gas and heating prices.
Repay over 15 years
During a visit to Kyiv last month, the IMF once more urged Ukraine to raise gas prices for domestic consumers and introduce a flexible exchange rate for the hryvnia currency, steps that the government has rejected.
A high-ranking Ukrainian government delegation visited China in September, when China's Export-Import Bank provisionally offered a $3-billion loan to help restore Ukraine's irrigation system.
The loan has to be repaid over 15 years. Agriculture Minister Mykola Prysyazhnyuk said the loan would be used to install and repair irrigation systems in southern Ukraine, with the aim of increasing grain output by 12 million tonnes, or around 50 per cent.
Last year, China lent Ukraine $3 billion for the agriculture sector and $3.7 billion for projects in the energy sector. As part of the deal, Ukraine exports around four million tonnes a year of maize to China.