SARAJEVO, Bosnia-Herzegovina (AP) — Western diplomats urged Bosnian leaders Thursday to continue moving toward NATO membership, saying it could bring security and improve people's lives. But a Bosnian Serb leader says Serbs will not let Bosnia join until the alliance resolves its differences with Russia.

The ambassadors of the U.S., Britain and NATO issued a joint statement saying, "If you want positive change ... moving toward NATO is a great way to do it."

Ordinary Bosnians are torn over the issue, with Croats and Bosniaks generally in favor, but Serbs, who are traditionally pro-Russian, strongly opposed to joining the Western military alliance.

The ambassadors said NATO is important not just for the security it offers but also because of "rule-of-law reforms that will help to improve the lives of ordinary citizens."

Milorad Dodik, who advocates Serb secession from Bosnia and a new Serb country in the Balkans, told The Associated Press this week that Bosnian Serbs will organize a referendum in their half of the country on whether they want to join NATO and said it will certainly result in a 'no'.

The warning comes ahead of a NATO summit in July and highlights the difficulties the alliance will have to win over Bosnia's Serbs, whom it bombed in 1995 to end the Bosnian war.

The peace agreement that followed the bombardment divided the country in two autonomous regions — a Russian-backed Serb one that opposes NATO membership and another shared by Bosniaks and Croats that is backed by the West and favors NATO. No decision can be made without consensus.

"The Russians and NATO are now at odds and they are playing out their differences around the world," Dodik said, insisting that Bosnia should "stay neutral."

"NATO officials are nervous and want to get everybody they can on their side ... but we have to protect our own interests," he said. "It is maybe the best to tell them to get back to us once they end their conflicts, and then we can talk about where we want to go."

Neutrality is not an option, according to security analyst Denis Hadzovic, echoing the opinion of Bosniak and Croat leaders.

"I see no alternative to Bosnia's NATO membership," he said, explaining that for small countries such as Bosnia it is dangerous not to be part of a bigger military alliance in a world threatened by nationalism, terrorism, the migrant crisis and the rise of populist forces.

Continuing to argue about it can lead to Bosnia's violent dissolution, he said, recalling that Ukraine lost a part of its territory because of its internal dispute over EU membership.