* EU looks at possible police mission to Ukraine
* Discusses more sanctions against Russia
* Minutes of an earlier meeting suggest gas sanctions not on table
By Justyna Pawlak and Adrian Croft
LUXEMBOURG, April 14 (Reuters) - European Union foreign ministers will hold talks on Monday to discuss how to toughen sanctions against Russia for its actions in Ukraine without losing the support of some EU governments worried about antagonising a power with an energy stranglehold over Europe.
Under discussion are possible new economic sanctions, as well as an EU mission to train police and other law-enforcement officials in Ukraine and the bloc's approach to issuing visas and trade with the Crimean peninsula, which was annexed by Moscow in March after popular protests toppled pro-Russian president Viktor Yanukovich.
Tensions between Russia and Ukraine escalated over the weekend, with Kiev announcing plans for a "full-scale anti-terrorist operation" against a rash of rebellions in eastern Ukraine that it says are inspired and directed by the Kremlin.
EU foreign policy chief Catherine Ashton expressed concern on Sunday over "the surge of actions undertaken by armed individuals and separatist groups in various cities of Eastern Ukraine".
"The Russian Federation is urged to call back its troops from the Ukrainian border and to cease any further actions aimed at destabilising Ukraine," Ashton said in a statement.
The U.S. Treasury Secretary Jack Lew said on Friday the Group of Seven leading rich nations would support increasing sanctions against Russia if Moscow escalates the crisis in Ukraine.
But a senior EU official said on Friday any wide-ranging economic measures would not be ready by Monday, with the bloc's 28 governments focusing on diplomatic efforts to calm tensions later in the week. Ashton is due to meet officials from the United States, Russia and Ukraine in Geneva on Thursday.
"The real question will be to see whether (EU) member states agree to ask (Ashton's office) to prepare an additional list of restrictive measures," he told reporters.
It is unclear what areas of the Russian economy, if any, could be subject to future EU sanctions. One EU diplomat said, however, that the bloc could agree on Monday to add names to a list of Russian and Crimean officials targeted by EU asset freezes and visa bans over Moscow's takeover of the peninsula.
In talks with industry representatives and officials from Ukraine last week, the EU's Energy Commissioner Guenther Oettinger said natural gas, Russia's key export product, would not be part of any sanctions, according to minutes of a closed-door meeting in Brussels seen by Reuters.
The EU is highly dependent on Russian gas deliveries, and the crisis over Ukraine has fanned concerns about future supply.
SQUABBLES OVER ENERGY
Russian President Vladimir Putin added to the tensions when he wrote to 18 EU leaders last week telling them Russia would cut gas supplies to Ukraine if it did not pay its bills and said this could lead to a reduction of onward deliveries to Europe.
Oettinger is expected to discuss Putin's warning with EU foreign ministers on Monday, according to a letter from European Commission President Jose Manuel Barroso to EU leaders on Friday, seen by Reuters.
In addition to energy issues, the bloc is also weighing the possibility of sending a mission of police and judicial advisers to Ukraine to help stabilise the country, as proposed by Britain, Sweden and Poland, and supported by Germany.
Such a mission - likely to irritate Russia - would seek to rebuild Ukraine's police and legal system in the short term to help combat sporadic violence in the country of 46 million people and lay the groundwork for implementing a proposed free-trade deal with the European Union.
The bloc also wants to define the legal aspects of its relationship with Crimea, including how visas are issued to residents of the peninsula, what passports and customs stamps are honoured, all of which will be discussed on Monday.
"It is important to show that there won't be a recognition of the annexation through the back door," says one diplomat. (additional reporting by Tom Koerkemeier, Luke Baker and Barbara Lewis in Brussels)