"We are here to say that these reports and text messages are untrue, that they are completely false, since we in the police and the military are solid, united behind the government," said Avelino Razon, the country's police chief.
His words were echoed by General Hermogenes Esperon, the military chief.
"This is our expression ... that our countrymen should not be concerned with rumours of destabilisation," he said.
The show of support came as thousands of Filipinos rallied across the country, calling on Gloria Arroyo to resign amid corruption charges.
Students, teachers, religious leaders and activists marched through 15 cities on Monday, the 22nd anniversary of the creation of the country's "people power" movement, following a series of corruption scandals involving Arroyo.
The former economist has survived three impeachment bids and more than 10 coup attempts, the last one just three months ago.
|Thousands across the country called |
for Arroyo's resignation [AFP]
The latest claims to affect Arroyo involve allegations that her husband and a close political ally received $130m in illegal payments in return for putting pressure on the government to approve an overpriced national broadband network contract with a Chinese corporation.
The pair deny the claims and Arroyo has vowed to see out her final term, which ends in 2010.
Political analysts say she will likely do so because besides enjoying the support of the security forces, she can count on the backing of the lower house of congress, and the powerful Catholic church has not come out directly against her.
A powerful council of bishops is to meet on Tuesday, however, to discuss the political situation.
Arroyo was reportedly warned last year about possible corrupt dealings with the ZTE Corporation, but signed the contract anyway, only to cancel it five months later.
The Philippine senate has launched an investigation into the case.
Arroyo has warned rivals against any attempts to remove her from power, saying a people's revolt for the third time would hurt the country politically and economically.
She said: "We all know I am not perfect ... but I have worked hard every day to achieve positive and lasting change for the nation."
Thousands disagreed with her, apparently, with between 4,500 and 6,000 marching on the streets of the capital, Manila, on Monday, and
smaller crowds demonstrating in other cities.
The protests were all held peacefully amid tight security.
None of the anti-Arroyo rallies has so far reached the scale that forced two former presidents - Joseph Estrada and Ferdinand Marcos - out of office.
Estrada, the last Philippine president to be forced from office in a "people power" revolt, told Al Jazeera: "If the people don't like her anymore, well it's time to go."
He said people felt that Arroyo had been insulting and fooling them throughout her presidency, and that now they had reached a limit.
"That is why so many different organisations are asking her to resign," added Estrada, a former film actor, who remains hugely popular among the masses despite being convicted of "plunder" in September last year.
He later accepted Arroyo's offer of a pardon.