More than 2,000 teachers and other employees in Croatia’s education system have rallied in the capital of Zagreb to press for higher wages after being on strike for nearly a month.

Carrying banners and blowing whistles, the protesters marched Wednesday through the city before gathering outside government headquarters in Zagreb.

The unions are demanding wage hikes but talks with the government so far have yielded no results.

Sanja Sprem of the Croatian teacher’s union says “it’s important to show the government that teachers are ready to fight for their dignity.” The teachers’ strike started last month, with different Croatian municipalities halting classes on different days. There are about 1,000 schools in Croatia with tens of thousands of employees.

Separately, Russia will deliver a sophisticated anti-aircraft missile system to Serbia even though the US has warned of possible sanctions against the Balkan country in the event of such purchases.

Russia’s state TASS news agency said Wednesday that the Pantsir-S system will be delivered to Serbia “in the next few months in accordance with the signed contract.” The US’s special envoy for the Western Balkans, Matthew Palmer, warned Serbia last week that the purchase of Russian weapons “poses a risk” of US sanctions.

“We hope that our Serbian partners will be careful about any transactions of this kind,” Palmer said in an interview with Macedonian television Alsat M.

Serbia remains a key ally of Russia even though it wants to join the European Union. Belgrade has pledged to stay out of NATO and refused to join Western sanctions against Russia over the conflict in eastern Ukraine.

Russia has been helping Serbia beef up its military with fighter jets, attack helicopters and battle tanks, raising concerns in the war-scarred Balkan region. During the bloody breakup of the former Yugoslavia in the 1990s, Serbia was at war with neighbors Croatia, Bosnia and Kosovo.

Serbian President Aleksandar Vucic said in a state TV interview on Tuesday that Serbia is purchasing defensive weapons from the Russians and that he wants to avoid any US sanctions “or confrontation with America.” “Serbia is arming itself because it is a free country surrounded by NATO-member states with which we want to be friends,” Vucic said, adding he won’t allow Serbia to “be as weak as it was in the 1990s.”

Agencies