China Sept exports surge, creating record surplus with U.S. despite tariffs

* Sept export growth at 14.5 pct y/y, vs forecast of 8.9 pct

* Sept surplus with U.S. widens to record high $34.13 bln

* Front-loading before tariffs kick in 'quite obvious' - economist

* Sept trade surplus at $31.69 bln, vs Aug total of $27.89 bln (Adds quotes, details, milestone)

By Elias Glenn and Stella Qiu

BEIJING, Oct 12 (Reuters) - China's vast export engine unexpectedly kicked into higher gear in September, producing a record trade surplus with the United States that could exacerbate the already-heated dispute between Beijing and Washington.

Analysts said last month's strong export growth - which might indicate U.S. tariffs are not biting much yet - is unlikely to be sustained.

But the robust numbers reported on Friday by China's customs agency - the last ones from China before U.S. congressional elections on Nov. 6 - could prompt a reaction from U.S. President Donald Trump.

September exports rose 14.5 percent from a year earlier, the fastest pace since February, the customs data showed. That was well above August's 9.8 percent and a Reuters poll forecast of 8.9 percent.

"The big picture is the Chinese exports have so far held up well in the face of escalating trade tensions and cooling global growth, most likely thanks to the competitiveness boost provided by a weaker renminbi," said Julian Evans-Pritchard, senior China economist at Capital Economics.

"With global growth likely to cool further in the coming quarters and US tariffs set to become more punishing, the recent resilience of exports is unlikely to be sustained."

YUAN DEPRECIATION

A weaker yuan, which has depreciated about 6 percent against the dollar this year, may have taken the sting out of the tariffs imposed on $250 billion of exports to the United States.

Despite concerns from some officials about the yuan's depreciation, U.S. Treasury staff have not recommended labelling China as a currency manipulator in a coming report on foreign exchange rate practices, according to media reports on Thursday.

China's politically-sensitive surplus with the U.S. was $34.13 billion in September, surpassing the record of $31.05 billion in August.

Beijing's export data has been surprisingly resilient to tariffs, possibly because companies ramped up shipments before broader and stiffer U.S. duties went into effect, raising concerns about a sharper drop in export strength once all tariffs kick in.

"The front-loading impact is quite obvious to me," said Betty Wang, senior China economist at ANZ in Hong Kong.

She cited a jump in exports of electrical machinery - the biggest export item from China to the U.S. - as a sign exporters might have pushed out shipments ahead of implementation of the latest tariffs on $200 billion in Chinese exports.