* If violence persists, EU should move to sanctions - Zaoralek
* Key moment will come after Ukraine government amnesty ends
* EU and US appear to be at odds on sanctions issue (Adds quotes by ministers, EU communique; note offensive language, paragraph 22)
By Luke Baker
BRUSSELS, Feb 10 (Reuters) - The European Union must be ready to impose sanctions on Ukraine if it persists in using violence against protesters, the Czech foreign minister said on Monday, warning against what he saw as Soviet-style authoritarianism.
Speaking before EU foreign ministers met in Brussels to discuss the Ukraine crisis, Lubomir Zaoralek said it was unacceptable to see human rights being blatantly violated on the borders of the European Union.
Protesters, now in their third month of street action against President Viktor Yanukovich, blame security forces for abductions, attacks on protesters and torching of their cars.
"It's something totally unacceptable, this violence and the role of the authorities in intimidation. It's something that is very close to our experience in the socialist past," Zaoralek told Reuters.
"I am absolutely convinced that if there is an escalation of violence, I see no chance to avoid sanctions. The EU must use all tools at our disposal," he said.
At least six people have died in occasional clashes between demonstrators and riot police in Kiev since protests erupted over Yanukovich's decision in November to drop a trade pact with the European Union and form closer ties with Russia.
Protest organiser Dmytro Bulatov says he was kidnapped, tortured and held for a week by unknown assailants.
French and German ministers said EU governments decided at Monday's meeting to hold the threat of sanctions in reserve in case the situation in Ukraine got worse.
"There was a consensus that we do not have to decide about sanctions yet, as long as we see some progress in the talks between the Ukrainian government and opposition," German Foreign Minister Frank-Walter Steinmeier told reporters.
"But if there is a time when ... the talks are blocked by Yanukovitch and his people, then the talks about sanctions will not become silent and that will be the time to decide about this question," he said.
France's Europe minister Thierry Repentin said no minister wanted "immediate and general sanctions, but ... to refer to targeted sanctions if the situation deteriorated further."
A communique issued by the ministers said the EU was "ready to respond quickly to any deterioration on the ground," which one EU diplomat said was a veiled threat of sanctions.
The communique said the EU was ready to work with international financial institutions to help Ukraine overcome its economic crisis provided a new government pushed through economic and political reforms.
Ministers also appeared to dangle the possibility of closer Ukrainian ties to the EU in future by saying that the proposed trade pact was not the "final goal in EU-Ukraine cooperation."
The reference was sought by Poland, which believes that the EU should offer Ukraine the hope of eventual EU membership to encourage a democratic opposition, diplomats said.
"The words mean what they say: That this is not the end and there could be more in the future," EU foreign policy chief Catherine Ashton told a news conference.
Polish Foreign Minister Radoslaw Sikorski warned the EU could face a refugee crisis if violence escalated in Ukraine.
"We can't ignore the threat that if the situation deteriorates, as it still quite possibly might, this is a nation of over 40 million people (and) the number of refugees would affect us all," Sikorski said.
"If there is a martial-law style crackdown in Ukraine, that entire generation of Ukrainians who are now demonstrating in favour of Europe will lose hope that things will improve in their lifetime," he said at a Brussels event organised by the European Council on Foreign Relations thinktank.
The United States and its European allies back opposition calls for constitutional reform that aim to create a technocrat government controlling the economy and security forces and acting independently of the presidency.
But the question of possible sanctions on Ukraine have become a point of divergence between the EU and the United States.
In secret recordings released on the Internet last week, Victoria Nuland, the U.S. assistant secretary of state for European affairs, was heard complaining to the U.S. ambassador to Kiev that the EU was too soft, and she suggested the United States should adopt a "fuck the EU" attitude.
While the United States is keen to pressure Yanukovich and a possible sanctions package is being prepared in Congress , EU member states are far more hesitant.
The crisis has become a proxy battle between the EU and Russia over influence in Ukraine.
Zaoralek said the key moment for the EU would be mid-February, when an amnesty offered by Yanukovich to the protesters is due to expire.
The amnesty, already rejected by most of the demonstrators, calls on pro-EU protesters to leave occupied public buildings in exchange for some detainees being set free.
"If after Feb. 17 the current government uses violence to suppress the opposition, the Maidan and the people, maybe that will be a concrete reason to use all possible tools which we have in the EU," said Zaoralek, referring to the central square in Kiev that is the focal point of the protests. (Additional reporting by Adrian Croft, Justyna Pawlak and Tom Koerkemeier in Brussels; Writing by Luke Baker in Brussels and Richard Balmforth in Kiev; Editing by Tom Heneghan Robin Pomeroy)