The friendly fire deaths bring to 171 the number of people reported killed since gunmen waving black flags of the Islamic State (IS) group began rampaging through the Muslim city of Marawi last week.
Shortly after the violence erupted President Rodrigo Duterte imposed martial law across the southern region of Mindanao, home to 20 million people, to quell what he said was an IS bid to establish a base in the mainly Catholic Philippines.
"It's very painful. It's very sad to be hitting our own troops," Defence Secretary Delfin Lorenzana told reporters in Manila.
"It's sad but sometimes it happens in the fog of war."
He initially said 10 soldiers died but national military spokesman Brigadier-General Restituto Padilla later confirmed 11 were killed.
Lorenzana also warned that many militants may have escaped, despite checkpoints throughout the city and surrounding it.
"We have reports they are going to some of the towns around Marawi city," Lorenzana said.
Adding to concerns about the rising threat of IS, Lorenzana said militants from Saudi Arabia, Chechnya, Yemen, Malaysia and Indonesia were among the dead.
The military has relentlessly dropped bombs and fired rockets at the militants, who have been hiding in residential areas of Marawi where local authorities believe about 2,000 people are trapped.
Local authorities have repeatedly warned that the trapped residents and hostages are in grave danger of being killed in the air assaults, and today repeated calls for them to end.
"We continuously appeal to the chain of command... To refrain from using airstrikes," Zia Alonto Adiong, a local politician and spokesman for the provincial crisis management committee, told reporters in Marawi.
The International Committee of the Red Cross on Wednesday called for a humanitarian ceasefire.
"We will be unrelenting in the pursuit of our mission. The drive, resolve of every AFP (Armed Forces of the Philippines) personnel in the air, ground and water remain undiminished," Padilla told reporters.
"We will incessantly push our way forward to retake the remaining part of Marawi and liberate the people that the terrorists continue to use as human shields."
The militants have murdered 19 civilians, the military has said, while insisting none have died in any air assaults or the intense street-to-street battles.
The clashes erupted when security forces raided a house to arrest Isnilon Hapilon, a veteran Filipino militant regarded as IS's leader in the Philippines. He is on the US government's list of most-wanted terrorists.
Authorities said they were taken by surprise when many gunmen emerged to protect Hapilon and then went on a rampage through Marawi, which has a population of 200,000.
The militants mostly belonged to a local group called the Maute, and the infamous Abu Sayyaf kidnap-for-ransom gang that Hapilon has helped lead for many years.
A Muslim separatist rebellion in the southern Philippines has killed more than 120,000 people since the 1970s.
The Maute, the Abu Sayyaf and other hardline groups have rejected the peace process.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
