Protesters opposed to military rule marched near the presidential palace in the Sudanese capital on Saturday for the second time in a week, television images showed, despite heavy tear gas and a communications blackout.
A Reuters witness said security forces fired tear gas to disperse the crowds on the 10th day of major demonstrations since the October 25 coup.
The Central Committee of Sudanese Doctors said 178 people were injured during Saturday's protest, with eight caused by live bullets.
In separate statements, the committee said security forces entered Khartoum Hospital and Port Sudan Hospital.
Internet service spotty
Protests against the coup have continued even after Abdallah Hamdok was reinstated as prime minister last month. The demonstrators have demanded that the military play no role in government during a transition to free elections.
A week ago, demonstrators began a sit-in at the gates of the palace before being dispersed. On Saturday they were met by security forces and turned back.
Internet services were disrupted in the capital, and residents were unable to make or receive phone calls, witnesses said, while soldiers and Rapid Support Forces blocked roads leading to bridges linking Khartoum with Omdurman, its sister city across the Nile.
Internet service began to return for at least some users late on Saturday.
Some people managed to post images on social media showing protests in several other cities, including Madani and Atbara.
In Omdurman, security forces fired tear gas at protesters near a bridge connecting the city to central Khartoum, another Reuters witness said.
'Chaos and abuses'
"Departing from peacefulness, approaching and infringing on sovereign and strategic sites in central Khartoum is a violation of the laws," SUNA state news agency reported, citing a provincial security coordination committee.
"Chaos and abuses will be dealt with," it added.
Protesters in Khartoum chanted: "Close the street! Close the bridge! Burhan we will come straight to you," referring to military leader and sovereign council head Abdel Fattah al-Burhan.
U.N. Special Representative to Sudan Volker Perthes urged Sudanese authorities not to stand in the way of Saturday's demonstrations.
"Freedom of expression is a human right. This includes full access to the internet. According to international conventions, no one should be arrested for intent to protest peacefully," Perthes said.
The military could not immediately be reached for comment.
Sources told Reuters they heard gunshots in the vicinity of the offices of UNAMID peacekeepers in Darfur on Saturday morning. UNMID is the acronym for the African Union-United Nations Hybrid Operation in Darfur.
Last Sunday, hundreds of thousands of people marched to the presidential palace and security forces fired tear gas and stun grenades to disperse them.
Forty-eight people have been killed in crackdowns on protests against the coup, the Central Committee of Sudanese Doctors said.