Ukraine's President Petro Poroshenko greets Ukraine rights activists taking part in a rally at Lafayette Square across from the White House in Washington, DC on September 18, 2014. (Mandel Ngan/AFP/Getty Images)

The White House rejected a plea from Ukraine’s president on Thursday for weapons in the fight against Russian-backed separatists, announcing a $53 million package of non-lethal aid instead.

In an address to a joint meeting of Congress, Ukrainian President Petro Poroshenko asked for fuller military assistance from the United States government, including both “lethal and non-lethal” equipment.

“Blankets and night-vision goggles are important,” Poroshenko said. “But one cannot win a war with blankets.”

He added, “I urge America to help us rise and be equal to its natural and manifest role. I urge America to lead the way.”

But the Obama administration has resisted providing arms directly to Ukrainian forces for fear of escalating the standoff with Russia. The White House has instead urged Russia to conduct negotiations between both sides.

President of Ukraine Petro Poroshenko asked the U.S. Congress for support in his country's conflict with Russia on Thursday, saying "aggression against Ukraine is a threat to the global security everywhere." (AP)

“We believe that the best way to resolve the differences between the Ukrainian government and the Russian-backed separatists is for the Russian government to use their influence with the separatists,” said White House press secretary Josh Earnest.

Following Poroshenko’s speech, the White House announced an aid package including $46 million in “security assistance” and $7 million in humanitarian relief. Counting the new funds, the United States has provided $219 million to Ukraine in 2014.

Despite the disagreement over lethal aid, President Obama and Poroshenko spoke warmly of each other at a White House appearance later in the day. Obama said the Ukrainian president was “the right man for the job,” and said the United States is “prepared to support Ukraine in negotiations with Russia.”

Poroshenko praised Obama for “defending democracy and freedom” and told him, “You are a friend.”

The White House said much of the equipment included in the latest assistance package will be useful for Ukrainian soldiers, despite the lack of weapons.

“I should point out that the security assistance that we are providing today does include the kind of valuable equipment that will be useful to the Ukrainian military,” Earnest said Thursday, including items such as body armor, helmets, vehicles, night and thermal vision goggles and other devices.

During his speech to Congress — which prompted several standing ovations — Poroshenko urged U.S. lawmakers “not to let Ukraine stand alone in the face of this aggression” and asked for non-NATO “special, non-allied partner status” for Ukraine.

Poroshenko compared the fighting in Ukraine to the Middle East. “Just like Israel, Ukraine has the right to defend her territory and it will do so, with all the courage of her heart and dedication of her soul,” he said.

The Washington visit came days after the United States imposed another round of sanctions against Russia in the wake of its annexation of Crimea. The sanctions announced Friday by the Treasury Department targeted the energy, defense and financial services sectors of the Russian economy.

Poroshenko is visiting several countries in an attempt to gather international support for his government. He visited the Canadian parliament Wednesday, where he praised Ottawa as “one of the soundest supporters of Ukraine.”

After his Thursday morning visit to Capitol Hill, Poroshenko had lunch with Vice President Biden at the Naval Observatory and then met with Obama at the White House.

Poroshenko told lawmakers that he was making extraordinary efforts to preserve a truce riddled with violations since it began on Sept. 5. In Kiev, Ukrainian military spokesman Col. Andriy Lysenko said that one Ukrainian soldier had been killed and three more wounded in the previous day.

The sides plan to return to the negotiating table Friday in the Belarusan capital of Minsk, where they will continue hashing out details of how pro-Russian insurgents will administer the territory that they have captured since the conflict started five months ago.

Michael Birnbaum in Kiev and Zachary A. Goldfarb in Washington contributed to this report.