Ukraine seeks EU support for Russia sanctions

European Parliament President Martin Schultz, left, welcomes Ukrainian President Petro Poroshenko, second left, during an EU-Ukraine summit at the European Council building in Brussels on Thursday, Nov. 24, 2016. At right is European Commission President Jean-Claude Juncker and second right is European Council President Donald Tusk. (AP Photo/Virginia Mayo) (The Associated Press)

European Council President Donald Tusk, left, walks with European Parliament President Martin Schultz, center, and European Commission President Jean-Claude Juncker prior to an EU-Ukraine summit at the European Council building in Brussels on Thursday, Nov. 24, 2016. (AP Photo/Virginia Mayo) (The Associated Press)

European Council President Donald Tusk, center, European Parliament President Martin Schultz, left, and European Commission President Jean-Claude Juncker, right, speak with the media during arrivals for an EU-Ukraine summit at the European Council building in Brussels on Thursday, Nov. 24, 2016. (AP Photo/Virginia Mayo) (The Associated Press)

Ukrainian President Petro Poroshenko is pressing top European Union officials to keep sanctions pressure up on Russia while the EU seeks reassurance that Ukraine is doing its utmost to battle corruption.

Poroshenko and the leaders of the EU's main institutions began a summit in Brussels Thursday aimed at underlining the strength of EU-Ukraine ties and addressing sectors like democracy, energy, trade and security.

The EU has committed almost 3.5 billion euros ($3.7 billion) to Ukraine over the past two years. It also launched a mission aimed at chaperoning the former Soviet Republic toward democracy.

But endemic corruption has undermined progress. Two high-profile reformist politicians resigned early this month in frustration.

Meanwhile Russia-Ukraine ties are deadlocked over Russia's annexation of Ukraine's Crimean Peninsula and support for pro-Russian insurgents in eastern Ukraine.