Ukraine President Volodymyr Zelensky is facing a big headache as international aid to its military is under threat of getting cut by political developments in the United States and western neighbor Slovakia.

The United States Congress passed a 45-day budget bill averting a government shutdown but it leaves out funding for Ukraine that President Joe Biden requested.

In Slovakia, the populist party Smer-SD led by former prime minister Robert Fico won parliamentary election on Sunday.

The Smer-SD party, which won 23.3 percent of votes and 42 seats in the 150-member legislature, campaigned to stop military aid to Ukraine.

Reports say the Smer-SD may form a coalition government with like-minded parties like the leftwing Hlas-SD which won 27 seats and the nationalist Slovak National Party which won 10 parliamentary seats.

Slovakia has been one of Europe's biggest donors to Ukraine as a share of its gross domestic product.

Analysts predict a Fico government could radically change Slovakia's foreign policy to resemble that of Hungarian Prime Minister Viktor Orban.