WASHINGTON

US Secretary of Defense Lloyd Austin will visit Slovakia and Bulgaria this week after attending a NATO Defense Ministers Meeting in Brussels, the Pentagon said Monday.

Austin will embark on the trip Tuesday to the Belgian capital, where he will hold talks with NATO allies "about all the things we’re doing as an alliance to bolster and support the deterrence capabilities on the Eastern flank," spokesman John Kirby said at a press conference.

From Brussels, Austin will travel to Slovakia, which was announced last week.

Kirby revealed Bulgaria as the third stop of the tour, during which Austin will meet with senior civilian and military leaders.

The visits come amid reports that the US is exploring sending Ukraine more weapons amid its war with Russia.

Bulgaria and Slovakia are the two NATO countries that have the S-300 missile system in their inventories.

The Russia-Ukraine war, which began on Feb. 24, has drawn international condemnation, led to financial sanctions on Moscow and spurred an exodus of global firms from Russia.

At least 636 civilians have been killed and 1,125 injured in Ukraine since the beginning of the war, according to the UN. It has warned, however, that the true toll is likely much higher as it has not been able to gain access to areas of increased hostilities.

Some 2.8 million people have also fled to neighboring countries, said the UN refugee agency.

*Kasim Ileri contributed to this report