A top U.S. diplomat on Thursday warned the Bosnian Serb leader that his threats to secede from Bosnia could lead to economic isolation of the Serbs who account for nearly a third of Bosnia's population.

The U.S. embassy in Sarajevo said in a tweet that Deputy Assistant Secretary of State Gabriel Escobar had warned Milorad Dodik, Serb member of the Bosnian presidency, "that threats of secession and rolling back reforms" will result in "nothing but isolation and economic despair."

At a news conference on Thursday, Dodik said secession is something that "will happen" because Bosnia is not functioning, but told reporters "we have no plan."

Dodik has long called for secession and recently said Bosnian Serbs would withdraw from the country's joint military.

Escobar reaffirmed Washington's firm commitment to the sovereignty and territorial integrity of Bosnia and Herzegovina, the tweet said.

The 1990s Bosnian war in which more than 100,000 died was ended by the U.S.-brokered Dayton peace deal, dividing the country into the Serb-dominated Serb Republic and a Federation dominated by Bosniaks and Croats, which are linked via a weak central government.