Gunmen opened fire in two mosques in Afghanistan late on May 19, killing at least 13 worshippers breaking their Ramadan fast, officials said.
In one of the attacks, in the central province of Parwan, at least 10 people were killed and 16 were wounded, security officials told RFE/RL.
General Alozai Ahmadi, the commander of Afghan security forces in Parwan, said an investigation is under way into the attack in Parwan's provincial capital Charekar.
"Unknown gunmen fired on people praying inside a mosque during iftar time," said Wahida Shahkar, spokeswoman for the governor of Parwan, referring to the meal eaten to break daytime fasting during the Islamic holy month.
The Interior Ministry blamed the attack on the insurgent Taliban. The Taliban denied responsibility and said Afghan security forces were to blame.
Parwan Province police chief Haroon Mubariz Parwan told RFE/RL that Islamic State (IS) militants are suspected of having carried out the attack.
Three other people were killed in a similar attack late on May 19 on a mosque in the southeastern Khost Province, Talib Mangal, a spokesman for the provincial governor, told RFE/RL.
Mangal said a child was also wounded in the attack in the Sabari district of Khost.
No one claimed responsibility for the Khost attack.
The security situation has been deteriorating in Khost in recent weeks. The police chef of Khost, Sayed Ahmad Babazai, was killed by a roadside bomb on May 8.
The United Nations has warned of an alarming spike in violence against civilians in Afghanistan. A shocking attack on a Kabul maternity ward last week killed 24 people, including newborn babies.
Violence increased even after a February 29 agreement between the United States and the Taliban on the withdrawal of U.S.-led foreign forces in exchange for Taliban security guarantees.
Afghan security forces on May 19 clashed with Taliban fighters around the city of Kunduz, a strategically important center that the militants have briefly captured twice in recent years.
Security forces largely repelled the Taliban offensive with the help of air support.
Assadullah Khalid, acting defense minister, said during a visit to the city that more than 50 militants and eight security force members had been killed.
The Taliban has rejected repeated calls for a cease-fire by the Afghan government. They deny any involvement in the maternity ward attack, for which Washington believes IS was responsible.
The United States has sent special peace envoy Zalmay Khalilzad to Qatar and Kabul to press the Taliban and the Afghan government and the Taliban to start stalled peace talks.
-- With reporting by Reuters