Bombardment by pro-government forces of rebel-held southwestern Syria forced three hospitals out of service overnight as a Russian-backed assault gathered pace, the Syrian Observatory for Human Rights and a medical relief group said.
The medical facilities were located in the towns of Saida, al-Jeeza and al-Musayfra near the Jordanian border to the east of Deraa city. The Syrian government has launched a major offensive to recover the area from rebels.
The Syrian government has previously denied targeting medical facilities in the seven-year-long war.
The United Nations says the offensive has so far forced up to 50,000 people to flee towards the Jordanian border. Jordan, which already hosts some 650,000 Syrian refugees, has said it will not open the border.
The UK-based Observatory says some 47 civilians have been killed since the government assault got underway on June 19.
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State-run TV station al-Ikhbariya said the electricity supply to Deraa city - which is divided between rebels and the government - had been cut because insurgents it identified as "terrorist organisations" had targeted a power line in al-Musayfra, some 20 km (12 miles) to the east.
Observatory Director Rami Abdulrahman said a total of five hospitals had been targeted in the campaign so far.
Ahmad al-Dbis, safety and security manager at UOSSM, a medical charity that works in opposition parts of Syria, said the bombardment had caused "material damage" to the three hospitals on Wednesday.
"In addition, a civil defence centre in al-Musayfra was struck and damaged," added Dbis, who is based in northern Syria.
The scope of the government attack widened further to target the rebel-held town Saida for the first time. Activists identified the warplanes which struck it as Russian.