The European Union has sent helicopters and firefighting teams to Serbia to help tackle wildfires that have affected more than 3,500 hectares of the Deliblato Sands nature reserve, as firefighters continue efforts to contain the blazes.

Serbia activated the EU Civil Protection Mechanism on August 21, requesting international assistance after struggling to contain fires that have burned for more than two weeks in the protected area about 80 km (50 miles) northeast of Belgrade.

The EU mobilised four firefighting helicopters from its rescEU strategic reserve in the Czech Republic, Romania and Slovakia, as well as ground teams from Germany and Romania, the European Commission said on August 24.

Romanian and Slovak helicopters were already operating at the fire, while two Czech helicopters were deployed and a German firefighting team was due to arrive on August 24, Serbia's Interior Ministry said on August 22.

The fires were at their most severe last week, when temperatures approached 40 degrees Celsius and strong winds complicated firefighting efforts. Authorities said on August 22 that the situation was more stable, but warned that the danger had not passed.

Difficult terrain and strong winds have made it harder for ground crews to contain the fires, which have threatened the protected nature reserve.

"Firefighting teams from Czechia, Germany, Romania, Slovakia have joined the fight against wildfires in Serbia, working alongside local responders," EU Commissioner for Preparedness and Crisis Management Hadja Lahbib said.

Serbia has also received assistance from Russia. An Ilyushin IL-76 firefighting aircraft from Russia arrived in the southern city of Nis last week to help tackle the Deliblato Sands fire.

President Aleksandar Vucic said on August 23 that Serbia had requested Russian assistance on August 17 and European assistance later, adding that both sides responded quickly.

The government's handling of the fires has drawn criticism, with opponents saying authorities were slow to seek international help and initially downplayed the severity of the situation.

Interior Minister Ivica Dacic said on August 7 that Serbia was capable of dealing with the fires itself, which was echoed by Vucic on August 16 when he said that Serbia had enough resources to cope with the situation.

Vucic rejected the criticism during a visit to the affected area on August 23, saying the authorities had been monitoring the fires and that strong winds and difficult terrain were the main challenges.

He said no one had been killed and no buildings had been destroyed, although three firefighters had been put in danger when a firestorm passed over them.

Serbia's Higher Public Prosecutor's Office said on August 22 that it would ask police to identify people suspected of spreading false information about the fires on social media, citing possible grounds for the offence of causing panic and disorder, N1 reported.

The authorities said the situation in the Deliblato Sands was significantly better than in previous days but that the danger had not completely passed.

Other major fires have been reported in Serbia's southwestern Stolovi mountain range, while neighbouring North Macedonia has also been battling wildfires.

Serbia is not a member of the EU but has access to emergency assistance through the bloc's Civil Protection Mechanism. Earlier this summer, Belgrade sent a firefighting helicopter and emergency response team to Spain to help tackle wildfires there.