Hague emphasized the point during an update on the Afghan situation delivered Wednesday to Members of Parliament.
"Our message to the Taliban remains that entering a peace process is a chance for Afghans to sit down together and help shape their country's future," he said in a statement.
Hague said there was a general increase in violence in Afghanistan since the start of the year. Insurgents typically kick of a spring offensive after the winter snow melts though Hague said the campaign was "largely ineffective."
International forces are handing over security to their Afghan counterparts in preparation for a 2014 withdrawal.
U.S. Defense Department spokesman George Little said Defense Secretary Chuck Hagel met in Brussels with Afghan Defense Minister Bismillah Khan Mohammadi on the sidelines of a NATO meeting.
"The ministers discussed planning for upcoming transfer to full Afghan security lead," Little said in a statement.