BEIJING, March 17-- European powers and Iran made little progress late Monday toward reaching an agreement to end the standoff over Tehran's nuclear program, as an end-of-March deadline closes in.

As Iran's Foreign Minister Mohammad Javad Zarif touched down in Brussels, the E-U's foreign policy chief Federica Mogherini described talks on Tehran's nuclear program as entering a crucial phase.

The talks involving Zarif and Mogherini came on the sidelines of an E-U foreign affairs meeting. Officials said the remaining stumbling blocks largely revolved around political issues like lifting sanctions and access for inspectors.

"The main difficulty in the talks with Iran is not only to move on several topics about the nuclear but especially to the possibility to control what is going on in the field and there are still some difficulties there and I hope there will be progress on this topic." Said Didier Reynders, Delgian Duputy PM & Minister for Foreign Affairs.

An agreement, that has slowly taken shape over the past 15 months, could see Iran freeze large parts of its nuclear program for a decade in exchange for a gradual end to international sanctions.

This week Zarif is also holding several days of talks with U-S Secretary of State John Kerry in Switzerland. While the Iran talks were widely discussed on Monday, E-U ministers also announced the bloc had deployed a new military assistance mission to the Central African Republic.

Ministers also discussed the ongoing violence in Libya as well as attempts to bring the two rival governments there together into a grand coalition to end the bloodshed.

Some officials said if that happened the E-U would consider sending peacekeepers while a few hinted at a military option if the crisis in Libya worsens.

"The creation of a government is the last opportunity for a peaceful solution. If that doesn't happen we need to start thinking of a plan B to finish the conflict". Said Jose Garcia-Margallo Y Marfil, Spain's Minister of Foreign Affairs.

Libya has become a multi-issue concern for Europe as the United Nations estimates 90 percent of African migrants and refugees reaching Italy are now transiting through the lawless nation.