Rumsfeld praised Croatia for the progress it had made in defence reform on its path to NATO and thanked Croatia for a planned increase in its military contribution to the NATO-led peacekeeping mission in Afghanistan.
The US defence secretary also thanked the Croatian government for its assistance in removing the consequences of Hurricane Katrina and congratulated Croatia on the launch of accession talks with the European Union.
The talks also focused on the continuation of defence cooperation between Croatia and the United States, which Roncevic said was Croatia's most important bilateral partner in the defence and security area, and on Croatia's desire to join NATO.
"Croatia continues pursuing its ambition," Roncevic told Croatian reporters. "We have so far been more focused on starting negotiations with the EU, but we are conducting this process simultaneously," he added.
The United States' support is crucial for Croatia's NATO membership bid. The US State Department is making it conditional on the arrest of fugitive general Ante Gotovina and his handover to the Hague war crimes tribunal.
"I told Secretary Rumsfeld that the position of the Croatian government is, regardless of the fact that the talks with the EU have started, that the Croatian government will persist in implementing the conclusions contained in its Action Plan and that the Government is committed to resolving this issue in full," Roncevic.
Roncevic said that Croatia would triple its troop contingent in Afghanistan in 2006, and that the present 50-strong military police team would be reinforced with an army company.
He went on to say that cooperation within SEDM was successful, adding that Croatia presided over the task force in charge of defence and military support for the non-proliferation of weapons of mass destruction, border security and counterterrorism.
The SEDM process began in 1996 as a regional initiative to serve as a bridge to Euro-Atlantic institutions, particularly NATO.
Ukraine joined SEDM as a full member on Tuesday, bringing membership to 11 countries. The other members are: Albania, Bulgaria, Croatia, Greece, Italy, Macedonia, Romania, Slovenia, Turkey and the United States.
The Washington meeting was also being attended by Moldova as an observer and by Serbia-Montenegro and Bosnia-Herzegovina as guests.