UPDATE 2-Hong Kong readies for further protests after huge, peaceful rally

* Hong Kong readies for more protests after huge, peaceful rally

* Organisers say 1.7 mln attended Sunday protest despite rain

* Protesters fear erosion of freedoms promised by China

* Trump hopes for 'humanitarian' resolution before trade deal

* Beijing warns against outside influence, pressures big companies (Adds details)

HONG KONG, Aug 19 (Reuters) - Hong Kong is gearing up for further protests this week after hundreds of thousands of anti-government demonstrators braved heavy rain to rally peacefully on Sunday, marking a change to what have often been violent clashes.

Sunday's massive turnout, which organisers put at 1.7 million, showed that the movement still has widespread support despite chaotic scenes last week when protesters occupied the Chinese-ruled city's airport.

Some activists had apologised for the airport turmoil and on Sunday night protesters could be seen urging others to go home peacefully.

Police said on Monday that while Sunday's demonstration was mostly peaceful, there were breaches of the peace in the evening when some protesters defaced public buildings and aimed laser beams at officers.

It was a far cry from the violent clashes between protesters and riot police throughout the summer, with activists storming the legislature and targeting China's main Liaison Office in the city. The weekend was also noteworthy for a lack of tear gas use by police.

The protests, which have presented one of the biggest challenges for Chinese President Xi Jinping since he came to power in 2012, began in June as opposition to a now-suspended bill that would allow suspects to be extradited to mainland China for trial in Communist Party-controlled courts. They have since swelled into wider calls for democracy.

Hong Kong returned from British to Chinese rule in 1997 under a "one country, two systems" formula that promised wide-ranging freedoms denied to citizens in mainland China, including an independent judiciary, but many in the city believe Beijing has been eroding those freedoms.

Aside from Lam's resignation, demonstrators have five demands - complete withdrawal of the extradition bill, a halt to descriptions of the protests as "rioting", a waiver of charges against those arrested, an independent inquiry and resumption of political reform.

One protester, speaking at a "citizen's press conference" on Monday, was asked what path the protests would take now, peaceful or violent.

“We have started our rallies very peacefully but after two and a half months it seems that the Hong Kong government has not responded to our five demands so one thing leads to another and it may cause escalation," the speaker, named Wang, said.