MANILA, Philippines--President Gloria Macapagal Arroyo adopted a contrite tone on Sunday after admitting she knew about possible corruption in a telecommunications deal with a Chinese company nearly six months before she cancelled it.

"We all know I am not perfect, but I have worked hard everyday to achieve positive and lasting change for the nation," said the former economist, who has seen off three impeachment bids and at least three coup attempts over allegations of vote fraud and corruption.

In a radio interview on Saturday, Arroyo said she was made aware in April of possible corruption in the $329 million deal with ZTE Corp, China's second-biggest telecoms equipment maker.

Arroyo said she was told about possible irregularities the night before she attended the signing ceremony in China.

"How can you cancel the night before when you are negotiating with a foreign country?," she said.

"The signing proceeded, but at the first opportunity, I spoke with the president of China to tell him that we have to cancel the project."

Arroyo scrapped the deal in October after a businessman testified in a Senate probe that the country's elections chief and Arroyo's husband had told him to abandon his bid for the broadband project.

The businessman said the deal was overpriced by $130 million to fund kickbacks to government officials.

The elections chief, who the businessman said threatened him and tried to bribe him, was forced to resign. Both he and the president's husband deny any wrongdoing.

Arroyo on Sunday defended her husband, a controversial figure who volunteered to leave the country in 2005 after allegations he and his son received kickbacks from gambling lords triggered a failed impeachment bid. He returned from the US a few months later.

"My family is not engaged in any business in government. It's not acceptable and we know that," said Arroyo in a speech she made at the presidential palace after Mass.

The ZTE scandal revived earlier this month when a former government official reiterated the kickbacks allegations.

The new testimony galvanized opposition groups, who along with some Catholic bishops, students and members of the business community, have renewed calls for Arroyo's resignation.

However, political analysts say her position is secure because the powerful Catholic Church has failed to come out directly against her and she enjoys the support of the military and lower house of Congress.

In the opposition-dominated upper house, senators said Arroyo had forced herself into a corner by admitting she knew of the alleged corruption.

"What President Arroyo did or did not do after she learned there was something wrong with the NBN (national broadband network) deal is the smoking gun that links her to the scandal," said Senate Minority Leader Aquilino Pimentel Jr.

Arroyo's final term runs out in 2010 and after defeating an impeachment bid late last year she is, by law, insulated from another for 12 months.

Opposition groups are planning anti-Arroyo rallies on Monday, which is the 22nd anniversary of the overthrow of dictator Ferdinand Marcos, and on Friday.

Earlier this month, around 10,000 people demonstrated against Arroyo in Manila's financial district, the biggest crowds since tens of thousands rallied in 2005 at the height of a scandal over alleged vote fraud.