A team of Pentagon officials is heading to Ukraine to help the country rebuild its fractured military, a mission that lawmakers and analysts expect will result in recommendations for greater military assistance in the country’s fight against pro-Russia separatists amid international outrage over the downing of a commercial airplane.

Within the next few weeks, a group of Defense Department representatives who specialize in strategy and policy will head to Kiev to evaluate specific programs that the United States may want to help bolster, said Army Col. Steve Warren, a Pentagon spokesman.

Their objective is to work with Ukrainians to “shape and establish an enduring program for future U.S. efforts to support the Ukrainian military through subject-matter expert teams and long-term advisers,” he said.

Rep. Duncan Hunter, California Republican, offered qualified support for the plan.

“Clearly, we have an interest in what happens in Ukraine and it’s far better to have an idea of where we can maximize any support we are willing to provide,” he said.

The U.S. is moving to bolster Ukraine’s defense infrastructure as Russian President Vladimir Putin faces increasing pressure to cut off support to separatists who have seized control of a swath of eastern Ukraine....