AP
Frequently mentioned as a potential 2016 White House contender, Cruz also will visit other Eastern European countries and Israel on a trip that could be seen as an attempt to build his foreign policy credentials.
Cruz told The Associated Press on Tuesday that he'll meet with political, military, business and religious leaders in each country but declined to provide details, citing security concerns. His office said the visit will include meetings with protest leaders in Ukraine, which has scheduled a May 25 presidential vote.
A Republican, Cruz is a member of the Senate Armed Services Committee. The trip is sponsored by Secure America Now, a conservative foreign policy group and Cruz will be the only lawmaker on the trip, his office said.
"Ukraine right now is facing an enormous threat from a resurgent Russia. (Russian President) Vladimir Putin has been quite naked about his desire to reconstitute as much as possible the old Soviet Union," Cruz said. "I have a particular responsibility to assess firsthand the current and future military threats that could jeopardize our safety and the security of our allies."
Cruz criticized the Obama administration as "tepid" in its response to the crisis in the Ukraine. He renewed his call for the U.S. to install anti-ballistic missile batteries in Poland and the Czech Republic as safeguards for Eastern Europe, and push for liquefied natural gas exports to reduce Ukraine's dependence on Russia.
He also said the U.S. should help create a board to bolster the value of Ukraine currency.
Cruz brushed off a question about his political future.
"The objective here is to learn and listen and see firsthand the challenges and threats facing our national security," he said.
Ukraine's caretaker government came to power in February following the ouster of Russia-friendly President Viktor Yanukovych after months of protests in Kiev, leading to the worst standoff between Russia and the West since the Cold War.
Russia later annexed Crimea, and on Monday, pro-Moscow insurgents in eastern Ukraine declared independence and also sought to join Russia. On Tuesday, the defense ministry said six servicemen were ambushed and killed and eight others wounded in fighting with insurgents.
Last week, the U.S. State Department issued a travel warning for U.S. citizens to defer all "non-essential" travel to Ukraine and avoid all travel within the eastern parts of the country. The warning cited the "possibility of violent clashes between pro-Russian and pro-Ukrainian groups and the presence of Russian military forces in the Crimean Peninsula and on the eastern border of Ukraine."