Secretary of State Hillary Clinton headed to Vietnam on Tuesday for talks on boosting trade as the United States bids to shore up its stuttering economy with an Asia-focussed export drive. She was to arrive after a trip to Mongolia, where vast natural resources including coal are fuelling an economic boom on China\'s door-step. Clinton will meet Vietnamese leaders in Hanoi, and sign several agreements covering education exchanges and commercial contracts. She will also Tuesday hold talks with representatives of the US and Vietnamese business communities. Beyond trade, Vietnam has made clear it welcomes a closer relationship with its former wartime enemies in Washington amid tensions with historic rival China over territorial disputes. \"I think one of the keys here is if you look at ASEAN, it\'s one of the fastest-growing middle classes in the world,\" a top State Department official told reporters travelling with Clinton, referring to the Southeast Asian bloc. \"And as you consider what will be an important ingredient in American economic revival, clearly the role of exports will be central, and particularly in Asia,\" he added, asking to remain anonymous. Later this week Clinton will host the largest ever gathering of American business leaders in the Cambodian city of Siem Reap to discuss ways of boosting US exports to the region. \"If you look at say... the top 1,000 American companies in the United States, the vast majority of American activity in Asia is with the top tier of those companies,\" the official said. \"And so what we\'re seeking to do is to encourage other companies who have never thought or had to export to do more in Asia as a whole.\" According to US government data, the United States last year ran a trade deficit of 13.2 billion dollars with Vietnam, but the Southeast Asian country\'s own trade-dependent economy needs a shot in the arm. Vietnam\'s pace of economic growth slowed to 4.38 percent in the first half of 2012, its most sluggish rate for three years, hurt by factors such as high inflation and Europe\'s economic woes. During her stop in Mongolia, Clinton called on Asian nations with closed political systems to heed calls for greater democracy, saying it would only help boost their economies. Without naming communist China or Vietnam, Clinton dismissed arguments that democracy was unsuited to Asia, that it threatened stability or was a privilege of wealthy Western nations. She said that while Asia did have examples of countries that have achieved initial economic success without substantive political reform, that was \"a short-sighted, and ultimately unsustainable, bargain\". During her Asia tour, Clinton will also head to the one-party state of Laos, in the first visit there by the top US diplomat in 57 years. For her Vietnam leg, the secretary of state is coming under domestic pressure to speak out more about human rights. Representative Frank Wolf, a Republican known for outspoken views on rights, on Monday demanded the removal of his country\'s ambassador to Vietnam ahead of Clinton\'s visit, accusing the envoy of failing to press the issue.