Poland’s Prime Minister Donald Tusk said Wednesday that its forces would further fortify the border with Belarus and can use “all available means” to defend the NATO nation’s frontier, after a soldier was seriously wounded with a knife by a migrant.

Tusk said that a buffer zone some 200 meters (660 feet) wide would be set up along the border, which is also the European Union’s eastern frontier, in addition to a 190-kilometer (118-mile) long metal barrier already in place to prevent an influx of migrants crossing from Belarus. Poland says the pressure of illegal migration is organized by Belarus and Russia.

Tusk said the government will make a decision on the buffer zone next week.

Tusk, together with the defense and interior ministers, visited troops, border guards and police forces securing the border following a knife attack on a soldier early Tuesday near the village of Dubicze Cerkiewne.

Officials said the soldier remains hospitalized in serious condition.

Officials said a migrant reached across the bars of the more than 5-meter (16-foot) high metal wall separating Poland and Belarus and stabbed the soldier in the ribs. Polish security forces were not able to detain the attacker because he was on the Belarus side of the barrier, officials said.