(Reuters) - European Union foreign ministers will discuss whether to increase sanctions on Russia and how to help Ukraine when they meet in Brussels next week, EU foreign affairs chief Federica Mogherini said on Tuesday.

"Next week we will have a ministerial meeting in Brussels on Monday and there will be a discussion there, but I would say not just on whether to increase the sanctions but most of all how to support Ukraine in these difficult times," Mogherini told reporters in Berlin.

Fighting between pro-Russian separatists and government forces in eastern Ukraine flared up again in the past week, with Kiev citing new evidence of Russian support for the rebels, despite a ceasefire agreed in Minsk on Sept. 5.

Russia denies being a party to the conflict and says it has not sent troops or weapons to east Ukraine.

"I hope we don't return to a situation of two or three months ago with violent clashes and daily killings," German Foreign Minister Frank-Walter Steinmeier said as he accompanied Mogherini to a conference on her first Berlin visit as the EU's high representative for foreign and security policy.

Troop movements around the Ukrainian-Russian border indicated that all sides were preparing for more fighting, he said.

"That has to be prevented," Steinmeier said.

The EU and the United States have imposed economic sanctions on Russia since March, when it seized the Ukrainian territory of Crimea. The sanctions have hurt Russia's economy and Western exporters with exposure to Russia like Germany.

Steinmeier and Mogherini said sanctions should only be part of the response to Russia but they were having an impact.

"The Russian economy has been affected - very seriously, in fact," Mogherini said.