Video caption Trump: "Anything I can do to help Canada, I will be doing"

Canadian PM Justin Trudeau has left Washington DC with assurances from President Donald Trump that he will assist Canada in its rift with China.

President Trump said he would do "anything" to help Canada during his upcoming meeting with Chinese President Xi Jinping.

Mr Trudeau said he expected the topic of two Canadians detained in China to be raised during that G20 meeting.

The PM was in the US capital city to discuss China and trade.

The diplomatic tensions between Canada and China have only worsened since Huawei executive Meng Wanzhou was detained in Vancouver at the request of the US in December.

American authorities are seeking Ms Meng's extradition on suspicion of fraud and breaching US sanctions on Iran.

Shortly after her arrest, China detained Canadians Michael Kovrig, a former diplomat, and Michael Spavor, a businessman, and has accused the pair of spying.

Their detention is believed to be a tit-for-tat retaliation, which Canada calls "wrongful" and "arbitrary".

Image copyright AFP Image caption Michael Spavor (L) and Michael Kovrig have been held since December

China also appears be using economic tactics to pressure Canada, with a handful of Canadian agricultural exports suddenly facing obstacles in getting to the Chinese market.

CBC News reported last week that Chinese Premier Li Keqiang refused a request to speak to Mr Trudeau by phone in January to discuss the cases of Canadians detained in China.

Speaking to reporters in Washington on Thursday, Mr Trudeau offered little detail on what actions Mr Trump might take to assist Canada on China.

Also on Mr Trudeau's agenda was a meeting with House speaker Nancy Pelosi and US Senate majority leader Mitch McConnell to press for the ratification of the United States-Mexico-Canada Agreement, or USMCA.

The trilateral agreement would replace an earlier North American free trade deal.

It was signed by the US, Mexico and Canada in November after months of negotiations and needs to ratified by all three partners to come into force.

USMCA will govern more than $1tn worth of trade between the countries.

Image copyright Getty Images Image caption PM Justin Trudeau and House speaker Nancy Pelosi had a wager over the recent NBA championships.

US Democrats, who control the House of Representatives, have expressed concerns over enforcement tools, labour and environmental protections, and pharmaceuticals provisions in the trilateral trade deal, slowing ratification efforts.

Mr Trudeau said he had a "very good" conversation with Ms Pelosi, who controls whether the trade bill is brought to the floor.

Mexico was the first country to ratify the agreement, which passed in the Mexican Senate on Wednesday.

Canada is moving ahead, introducing legislation in May after Mr Trump lifted tariffs on steel and aluminium imports from Canada and Mexico.