Burmese opposition leader Aung San Suu Kyi left one of the biggest rallies of her election campaign, telling aides she felt unwell.

The 66-year-old pro-democracy leader flew from Rangoon to Mandalay, Burma's second largest city, Saturday, part of a rigorous campaign schedule ahead of by-elections on April 1. But after speaking for several minutes, Aung San Suu Kyi left the stage, telling aides she felt weak.

Doctors and aides say she was taken to a hotel room to rest and is feeling better.

Before stepping away, Aung San Suu Kyi praised the crowd, saying it was the largest she had since she helped lead the country's 1988, pro-democracy uprising.

“It is difficult to achieve democracy. And after we achieve democracy, it is hard to maintain. We have to do a lot of work, and we have to take things slowly.''

Aung San Suu Kyi is running for parliament in Kawhmu, a poor district south of Rangoon.

The National League for Democracy is attempting to return to parliament for the first time since its landslide electoral victory two decades ago. The military prevented it from taking power at that time.

The party refused to participate in elections in 2010 because of rules that ensured victory by a pro-military party and prevented Aung San Suu Kyi from being a candidate. But the government that came to power as a result has instituted a number of democratic reforms, including allowing the National League for Democracy to re-register as a political party.

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SOUNDBITES:

1. (Burmese) MYANMAR OPPOSITION LEADER, AUNG SAN SUU KYI, SAYING:

“When I see the people of Mandalay, it gives me strength, and also hope. I see that there are a lot of opportunities to do what we want to do for our country.''

2. (Burmese) MYANMAR OPPOSITION LEADER, AUNG SAN SUU KYI, SAYING:

“It is difficult to achieve democracy. And after we achieve democracy, it is hard to maintain. We have to do a lot of work, and we have to take things slowly.''

3. (Burmese) MONK, U THAYZA, SAYING:

“Change is not just a wish. For the sake of all the people, and not only for the sake of Auntie Su. We have to start the change in ourselves, then other people will change. Then the society, then the country. If the whole country changes, the whole country will develop.''

4. (Burmese) MANDALAY RESIDENT, WIN MIN THANT, SAYING:

“Not everyone in this country has the freedom to start a business. There has to be a level playing field for starting businesses.''

5. (English) ITALIAN TOURIST, UNNAMED, SAYING:

“We come here because of this very famous lady all over the world, and I love her.''