Protesters were expected to gather in downtown Hong Kong on Saturday - the latest in a series of anti-government demonstrations that have plunged the Chinese-ruled city into its worst political crisis in decades.
"The remarks have distorted the truth, condoned the offenders, flagrantly interfered with Hong Kong affairs, which are China's internal affairs, and again revealed the hypocrisy, hegemonic thinking, and prejudice of American politicians", the statement read.
"It's "now or never" for Hong Kong", said a 33-year-old accountant who gave her surname as Wong.
In a separate statement, the office opposed remarks made by Ms Federica Mogherini, the High Representative of the European Union for Foreign Affairs and Security Policy.
"All of a sudden, these people got arrested", said Jane Li, a Coquitlam resident and member of Vancouver Hong Kong Political Activists, a student group.
Pro-democracy protesters march in the rain in central Hong Kong on Saturday.
The violence has damaged Hong Kong's reputation for stability and prosperity.
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The move by Telegram comes as Hong Kong police arrested a number of prominent activists and three lawmakers on Friday.
The protests have expanded into a wider pro-democracy push and a rejection of attempts by Beijing to curtail the freedoms of the semi-autonomous territory. And US President Donald Trump said Washington's economic pressure on China was responsible for preventing the authorities from carrying out a harsher crackdown against demonstrators.
"Technically speaking, given the complexity of the modern Internet including technologies like VPN, cloud and cryptographies, it is impossible to effectively and meaningfully block any services, unless we put the whole Internet of Hong Kong behind large scale surveillance firewall".
Two of the Umbrella Movement's leaders, Joshua Wong and Agnes Chow - both still well-regarded among the city's youth - were arrested in dawn swoops on Friday and appeared in court accused of "inciting others to take part in unauthorised assembly" among other charges.
Businesses in the financial hub - from airline Cathay Pacific to the city's metro operator - have also been squeezed by Beijing for harbouring apparent supporters of the pro-democracy movement.
Protesters have been throwing petrol bombs toward police lines, according to reports by the Reuters news agency.
China on Thursday completed what it called a routine rotation of the air, land and maritime forces stationed in the former British colony, which has been rocked since June by a wave of sometimes violent demonstrations.
But on Saturday afternoon tens of thousands of protesters under a colourful canopy of umbrellas - many in their signature black T-shirts - defied the order and marched through Hong Kong island chanting "reclaim Hong Kong, revolution of our times". "The situation is far more complicated than most people realize".