Togolese authorities have blocked internet access as opponents of President Faure Gnassingbe marched for a second day against his family's 50-year rule.
Hundreds of protesters marched from the opposition stronghold of Be towards a meeting in central Lome, the capital, on Thursday, a witness said. Police later fired tear gas to disperse the protesters.
The scale of this week's protests, which the opposition said were attended by hundreds of thousands of people, represented the biggest challenge to Gnassingbe's rule since the aftermath of his ascension to power in 2005.
READ MORE: Togo protesters demand constitutional reform
US-based company Dyn, which monitors the internet, said traffic dropped off at 09:00 GMT in what critics said was a move by the government to suppress protests as other African governments have done.
Residents said that text messages had also been blocked.
The communications minister could not immediately be reached for comment on the cuts.
Analysts said Gnassingbe might find himself isolated amid growing criticism of autocratic rule in West Africa.
"The president's position is very fragile, and we do not think his peers in ECOWAS or his friends in Europe will help him if things get ugly," Francois Conradie, head of research at NKC African Economics, said.

President Faure Essozimna Gnassingbe came to power in 2005 following the death of his father who ruled the country for nearly 40 years [Denis Balibouse/Reuters]
Gnassingbe, who took power after his long-ruling father's death, has sought to appease opponents by introducing a draft bill to reform the constitution this week.
Such changes would reintroduce a two-term limit that was scrapped by the late Gnassingbe Eyadema in 2002.
But opposition leaders are sceptical that this would apply retroactively, meaning the current president might stay until 2030. They have called for his immediate departure.
Adama Gaye, a political analyst and author, said the opposition portion of the Togolese population is "fed up with the fact that it's the same family which has been ruling the country" for five decades
"Faure Gnassingbe is now facing the battle of his life because the population of Togo is young," Gaye told Al Jazeera from Dundee, Scotland.
"They are determined and they are taking advantage of the technological advances and internet, and also of some progress that has been made in democratisation in others parts of the continent, such as in Kenya recently," referring to a ruling by the East African country's Supreme Court to annul the result of last month's elections citing "irregularities and illegalities".
Togo, a regional financial hub that aspires to be an "African Singapore", is at odds with West African neighbours, which mostly have laws restricting presidential mandates.
Togo along with The Gambia voted in 2015 against introducing term limits across the 15 members of the ECOWAS regional body, which Gnassingbe currently chairs.
Source: Al Jazeera and news agencies
Africa Togo Politics