As leaders from European Union countries prepare to meet in Brussels on Wednesday to debate imposing sanctions against Russia, a number of recent events will be fresh in the delegates' minds:

On Monday, a Ukrainian military plane was downed in eastern Ukraine, with Kyiv claiming Russia was responsible for the attack. Ukraine said Russia had used a missile to shoot down the plane, which was flying near the border that separates the two nations.

OSCE says separatists unwilling to engage

On the same day, a group known as the Trilateral Contact Group issued a statement on the website of the Organization for Cooperation and Security in Europe (OSCE). The group consists of senior representatives of Ukraine, Russia and the OSCE. The group said that a planned video conference with pro-Russian separatists occupying cities in eastern Ukraine did not take place as hoped. The group, expressing its concern that no such contact between the parties in the Ukrainian conflict, said the lack of consultations was due to "a lack of willingness on the side of the separatists to engage in substantive talks on a mutually agreed ceasefire."

The Trilateral Contact Group says that a ceasefire would need to include OSCE observation that the truce was being maintained, the implementation of effective border monitoring, the release of all hostages, and the start of inclusive dialogue.

Following an invitation from Moscow on Monday, OSCE observers are set to begin monitoring border crossings between Ukraine and Russia on Wednesday.

US on its own?

Despite the concession from Russia, it appears likely that the West will go ahead with harsher sanctions against Moscow. The US hopes to align with the EU on fresh sanctions, but has said it could go it alone if the EU is not willing to ruffle feathers in Russia, a country with strong economic ties to the EU.

In a telephone conversation between US Vice President Joe Biden and Ukrainian President Petro Poroshenko, Biden told Poroshenko "that the United States was engaging with European leaders to discuss the imposition of costs on Russia for its continued escalation of the conflict."

US President Barack Obama and German Chancellor Angela Merkel also spoke on the phone on Tuesday. The White House released a statement saying the two leaders were in agreement "that Russia must take immediate steps to de-escalate the situation in eastern Ukraine amid the ongoing violence there."

mz/msh (AFP, AP)