(CNN) -- Indonesia's president, Susilo Bambang Yudhoyono, has apologized to Singapore and Malaysia for the hazardous air pollution caused by smoke from forest fires raging in his country.
Jakarta has sent planes, helicopters and an extra 3,000 personnel to fight the fires, which have been blamed on the clearing of land for palm oil plantations
"For this incident, I, as President of Indonesia, would like to apologize to Singapore and Malaysia and ask for their understanding. Indonesia did not want this to happen and we are trying to address this problem responsibly," he told a news conference on Monday evening.
Schools in many areas of Malaysia were closed on Monday and a state of emergency was declared in two southern regions after the country's air pollution scale spiked to hazardous levels on Sunday morning, Bernama, Malaysia's state news agency reported.
The country's air pollution scale exceeded 700 in two areas of Johor state. According to the index, a reading above 300 is considered hazardous.
"The schools are ordered to be closed as a precautionary measure since the bad air quality will affect the health of students," Second Education Minister Datuk Seri Idris Jusoh said.
Classes were back to normal for most schools on Tuesday as the air quality improved.
Shifting winds also allowed Singapore, which has been enveloped in smog for most of last week, to breathe easier.
The city's air pollution index stood at 52 at 11 a.m. local time on Monday, falling after the wind direction changed to southerly from southwesterly on Sunday.
Last week, the index hit its highest levels since 1997, with a reading of 371. The city's National Environment Agency said air quality becomes "very unhealthy" when the index passes 200.
Fires have raged in several spots on the island of Sumatra for more than a week, spreading acrid smoke to Singapore and Malaysia.
Authorities have been using three helicopters to "water bomb" the flames and in the past four days 7,000 liters of water have been dumped on the areas hit by the fires. A Cassa aircraft is also being used to seed clouds in attempt to create rain.
On Tuesday, Jakarta sent 3,000 firefighters, military and police personnel to reinforce the 2,000 already working to extinguish the fires in Sumatra, where 265 locations have been identified as hotspots.
"I have given instructions to mobilize the power we have, the resources we have including funding. There should be no obstacles in disbursing these funds," President Yudhoyono said.
According to the US-based World Resources Institute, most of the fires are on land owned or managed by timber companies and palm oil plantation owners.
Last week, it released a list of 17 timber companies and 15 palm oil plantation operators, including two headquartered in Singapore.
The chief of Indonesia's National Disaster Agency, Syamsul Maarif has said that the government is investigating which companies operating in Sumatra may have caused the fires.
Singapore said it would take legal action against local companies found to be involved and pressed Indonesia to provide evidence, the New Straits Times reported.
"We will offer no succor or refuge if the action of the companies have indeed been illegal in Indonesia and impacted on Singapore," Foreign Minister K. Shanmugam said.
The minister added that he would raise the issue at the upcoming meeting of foreign ministers from the Association of Southeast Asian Nations (ASEAN).
Authorities in Singapore are anxious to avoid a repeat of the 1997 Southeast Asian haze, which the government estimates cost $9 billion in health care costs and disrupted air travel and business.
Journalist Katie Hunt wrote and reported from Hong Kong, CNN's Kathy Quiano reported from Jakarta