EU officials are expected to press Russian President Vladimir Putin to take a stronger line on Syria during a summit in St Petersburg.
EU nations want Russia to put pressure on its ally to withdraw heavy weapons from cities and comply fully with envoy Kofi Annan's peace plan.
Russia and China are also resisting US and EU calls to condemn President Bashar al-Assad and seek his removal.
Meanwhile, Assad told parliament that "foreign meddling" was to blame for Syria's divisions.
Assad reiterated that the only way to resolve the crisis was through political dialogue.
However UN-Arab League envoy Kofi Annan has expressed frustration that Assad was not turning his words into actions.
The UN currently has a team of observers in Syria trying to monitor a ceasefire, but violence has continued across the country.