* President's gesture does not impress protesters
* Yanukovich mulls choice for new PM
* Lavrov criticises West for Ukraine policy
By Richard Balmforth
KIEV, Feb 14 (Reuters) - Ukrainian authorities on Friday provisionally freed the last 234 detained protesters under an amnesty offer aimed at defusing protracted street unrest, but activists decried the move as a sham and pressed for further concessions.
President Viktor Yanukovich's government has fixed Monday as the deadline for all occupied municipal buildings to be cleared of protesters and barricades to be removed from city centre roads in the capital Kiev in exchange for the release of the detainees and a possible future pardon.
Yanukovich negotiated the amnesty offer through parliament to try to take the sting out of street protests in Kiev and elsewhere in Ukraine that have kept him on the back-foot since he spurned a trade pact with the European Union in November.
With much of downtown Kiev a fortified camp where hundreds of "Euro-maidan" activists keep up protests behind barricades and sandbags, Yanukovich wants to tamp down tension before he picks a new prime minister, possibly as early as next week.
But with protesters highly suspicious about virtually any offer from Yanukovich's side, there seemed little chance of them relinquishing control of the streets by next week, though they said late on Friday that they might allow traffic to pass on the main road leading to government headquarters.
Though police released the last of 234 detained protesters on Friday, criminal charges have not been lifted against them.
They face prosecution at some point in the future for participating in "mass disorder" - a charge carrying a sentence of several years in prison - unless their comrades leave occupied buildings and clear blocked roads.
General prosecutor Viktor Pshonka said on Friday authorities would immediately begin considering dropping charges if buildings were cleared and key roads in the capital re-opened by Monday. But opposition parties and radical protesters, who clashed violently with police last month, said they wanted all charges dropped immediately.
"We have people being released from jail but kept under house arrest, that is to say they are deprived of their rights, and there is a criminal case hanging over each one of them. This is not an amnesty. This does not meet the conditions of the opposition," Rostislav Pavlenko, a member of opposition leader Vitaly Klitschko's party, Udar (Punch), was quoted as saying by the Russian news agency Interfax.
At least six people have been killed in clashes with riot police - unprecedented in the 22 years since Ukraine gained independence - since thousands of protesters rebelled against Yanukovich's sudden move to snub the EU in favour of forging closer economic ties with former Soviet master Russia.
The crisis has triggered a geopolitical tussle between East and West: Russia is beckoning Yanukovich with a $15 billion aid package to plug holes in Ukraine's heavily-indebted economy while the United States and its Western allies have urged him to move back towards an IMF-backed deal with Europe.
The East-West rivalry flared anew on Friday when Russian Foreign Minister Sergei Lavrov, meeting Germany's Frank-Walter Steinmeier in Moscow, accused the EU of seeking to create a "sphere of influence" on its borders.
"Dragging Ukraine to one side, telling it that it needs to choose 'either or', either with the EU or with Russia, (the European Union) is in fact trying to create such a sphere of influence," Lavrov said.
There have been no street violence in Kiev for three weeks.
But Western governments are worried about an escalation of conflict and breakdown of law and order unless Yanukovich meets opposition demands to allow them to form a government that could act independently of him.
They are also pressing him to change the constitution, under which his powers would be reduced and which would mean presidential elections before the scheduled date in March 2015.
A pivotal decision will be who Yanukovich names as his candidate for prime minister to replace the Russian-born Mykola Azarov, whom he sacked on Jan. 28 in a vain attempt to appease the protesters.
He has until the end of the month to reach a decision although parliament speaker Volodymyr Rybak was quoted by Interfax on Friday as saying he thought Yanukovich might present his choice to parliament next Tuesday.
With the hryvnia under devaluation pressure, he has to find a new steward of the economy quickly.
(Additional reporting by Natalia Zinets and Pavel Polityuk; Writing By Richard Balmforth)