Thousands of American volunteers are hoping to help fend off the Russian military from pushing further into Ukraine.

Up to 3,000 U.S. volunteers have now stepped up to respond to Ukraine's call for more defenders to fight for their country, the Ukrainian Embassy in Washington has confirmed. Thousands of Americans are now willing to serve in an international battalion that will help the Ukrainian resistance against Russian President Vladimir Putin's war. Many more have also signed up for the gargantuan task of fighting off the Russian military, a lot of which have come from other post-Soviet states such as Georgia and Belarus.

One of the thousands of U.S. volunteers who have responded to Ukraine's call to defend against Putin's war is Matthew Parker, an American veteran who served in the U.S. Army for 22 years, VOA News reported. Parker recounted how Putin's war made him think of a fellow soldier he served with, a Ukrainian American who said he had family back home in Ukraine.

"I had a soldier in Iraq with me who was from Ukraine. He became an American citizen, joined the Army, and he told me about his home," Parker shared. "He told me about his family and how proud they were. I remember him telling me about his little sister. Now...I'd like to think that by going to Ukraine, maybe I protect his mother, or his little sister or his home. Maybe in some small way, I say thank you to him for serving by doing something like this."

Parker, whose 22 year experience in the U.S. Army has brought him to Bosnia and Iraq, is just one of the thousands of men and women who are responding to Ukraine's call to help resist the Russian military, which began their assault on the country on February 24.

On Thursday, Ukrainian President Volodymyr Zelenskyy spoke of an "international legion" of 16,000 foreign volunteers who are being asked to "join the defense of Ukraine, Europe and the world." In an emotional video posted to his Telegram channel, the Ukrainian president remarked, "We have nothing to lose but our own freedom."

According to Parker, who is also a father of four grown children, the decision to fight alongside Ukraine came even before Zelenskyy appealed to the international community to send backup. The former U.S. Navy service member said that he and 12 other veterans planned to fly to Poland and travel to the Ukrainian border to register for territorial defense. But the plan became clearer when Zelenskyy established a system to call for volunteers to come to Ukraine.

Parker, who is from South Carolina, said that his service in the U.S. Army as an instructor and combat leader has honed his skills in combat situations. He said, "They can place me where they need me. Or they can only leave me as an instructor with the legion to teach Ukrainians how to use different weapons systems."

Ukraine needs as much help as it can get in facing Putin's war. Parker said that the country was facing a "bully" and "someone who does not honor international law, who does not care about women and children." He added that he and his comrades had "fought this type of people before."

On Sunday, Zelenskyy reflected on how in Ukraine, a family of four, with two children, were killed by Russian forces in Irpin as they were trying to flee the city, Axios reported. The Ukrainian president said, "Instead of forgiveness, there will be judgment."

According to Al Jazeera, Putin's Russian military have intensified shelling Ukrainian cities in the center, north, and south of the country.Ukrainian presidential adviser Oleksiy Arestovich said that the "latest wave of missile strikes came as darkness fell," describing a "catastrophic" situation in the capital of Kyiv.