To defeat pro-Russian rebels, Ukraine needs more troops, Yuriy Biriukov, an adviser to Ukraine’s defense minister, said this week. Ukraine must increase its military budget by 100 billion hryvnia, or $4.65 billion, per year to sufficiently increase the number of professional troops in its armed forces, Biriukov said, DefenseNews reported Wednesday.

A bigger defense budget is necessary to build a military in which "the ratio of professional troops to conscripts is 60 to 40," Biriukov told local broadcaster Hromadske TV. Roughly 50,000 of Ukraine’s 250,000 troops have professional contracts. This year, the Defense Ministry has a budget of some 40 billion hryvnia.

Ukrainian President Petro Poroshenko signed a law in March that called for growing the country’s military personnel to 250,000. Ukraine also hopes to modernize its weapons and equipment. State-run defense giant Ukroboronprom claims it has supplied 3,936 units of new military equipment to the country's armed forces so far this year.

Ukraine's soldiers have been under attack from pro-Russian rebels in east Ukraine since April 2014. Kiev said Monday that the rebels had four of its soldiers and injured 15 over the weekend in a conflict area near rebel-held Donetsk, the BBC reported.

“Our army has been systematically destroyed and disarmed, ...and its best personnel dismissed,” Deputy Defense Minister Petro Mehed said last year.

Ukraine, the United States and NATO have blamed Russia for backing the rebels by arming them with heavy weapons. A peace plan was established in February, but the government and rebels have largely ignored the agreement.

Some Ukraine soldiers have complained that Kiev is not fully supporting them against the rebels. “Why doesn’t the president come here?” Vasyl, a Ukrainian army soldier, told the Financial Times. “Then he’ll see firsthand how poorly supplied we are — although we’re dodging artillery almost every day under this ceasefire he himself brokered.”