* More officials will be put under EU travel bans, asset freezes
* Work nearly finished on possible more extensive sanctions
* EU could hold emergency summit next week to impose extra sanctions (Releads with decisions, adds quotes)
By Justyna Pawlak and Adrian Croft
LUXEMBOURG, April 14 (Reuters) - The European Union agreed on Monday to step up sanctions against Russia over Ukraine by expanding a list of people targeted with asset freezes and visa bans, and said the bloc could hold an emergency summit next week to adopt further measures.
EU foreign ministers acted in response to a deepening of the crisis in Ukraine, where pro-Russian separatists ignored an ultimatum on Monday to leave occupied government buildings in the east of the country.
"We have agreed ... to expand the sanctions," British Foreign Secretary William Hague told reporters after the meeting in Luxembourg.
Over the next few days, EU officials will work on a list of new names of people they believe played a role in violating Ukraine's territorial integrity.
They will be added to a list of 33 Russian and Ukrainian officials already under EU asset freezes or visa bans.
The ministers again held out the threat of imposing farther-reaching sanctions on Russia, such as trade and financial restrictions, if Moscow took further steps to destabilise Ukraine.
The EU's executive Commission has almost finished work on preparing those potential sanctions but officials left vague exactly what Russia would have to do to trigger them.
Any further tightening of sanctions will likely depend, in part, on the outcome of a meeting between the EU, the United States, Russia and Ukraine planned for Geneva on Thursday.
"If it is necessary, there may be a meeting of heads of state and government next week at European level, which may adopt new sanctions," French Foreign Minister Laurent Fabius told reporters. "The goal is to show firmness while keeping a dialogue open," he said.
Hague said a decision on whether to hold an extra summit would be taken by EU leaders and would "depend on how the situation develops ... over the next few days".
UK ACCUSES RUSSIA
Hague earlier said there could be no doubt that Moscow was behind the destabilisation of eastern Ukraine.
Polish Foreign Minister Radoslaw Sikorski also pushed for the sanctions list to be expanded.
But other governments were more cautious, underscoring concerns in parts of Europe about antagonising a power with an energy stranglehold over the bloc, and put their faith in Thursday's talks.
Russian President Vladimir Putin wrote to European leaders last week warning them Russia would cut natural gas supplies to Ukraine if it did not pay its bills and said this could lead to a reduction of onward deliveries to Europe.
The EU foreign ministers asked the European Commission to reply to Putin "in order to agree on consultations with Russia and Ukraine with a view to ensuring security of (gas) supply and transit," they said in a statement.
Germany said the Geneva meeting could help calm tensions even though the option of sanctions remained on the table.
Jean Asselborn, Luxembourg's foreign minister, said sanctions wouldn't "resolve the problem".
"Our main task today is to do everything so that this conference on Thursday in Geneva can take place and take place in a calm atmosphere," he said.
The ministers agreed some steps to help Ukraine overcome its deepening economic crisis, approving a package of nearly 500 million euros ($685 million) worth of trade benefits, which include the removal of duties on a wide range of agricultural goods, textiles and other imports, and approving a decision to provide up to one billion euros in financial aid to Ukraine.
Four Ukrainians were also added to a list of people targeted with EU sanctions over misappropriation of state funds.
Ministers did not reach a firm decision on a possible EU mission to train police and other law-enforcement officials in Ukraine to help stabilise the country, as proposed by Britain, Sweden and Poland, and supported by Germany. (additional reporting by Tom Koerkemeier, Luke Baker and Barbara Lewis in Brussels; Editing by Giles Elgood, Philippa Fletcher and Peter Graff)