The bombing at a luxury hotel in Jakarta has underscored the enormous difficulties in protecting a population from terrorist acts. It also confirms the difficulties governments in Southeast Asia face in fighting terrorism.

After a bombing on the resort island of Bali killed 202 people last year, Indonesian authorities pledged to increase security and crack down on terrorism.

But terrorists were still able to set off a powerful bomb Tuesday at a prestigious American hotel in the heart of the Indonesian capital. The blast at the J.W. Marriott hotel killed at least 10 people and injured dozens.

David Wright-Neville, a former senior terrorism advisor in the Australian government, said there are just too many easy targets in Indonesia, and across Southeast Asia, to protect them all. "I think that there is such a proliferation of potential targets - whether they be nightclubs or bars, or whether they be hotels or buildings that house Western companies, or even those sort of buildings that are representative of the secular governments of these countries, be they parliaments or police stations or whatever - I simply think it's a lot to ask of the authorities in these countries in Southeast Asia to mount the kind of security necessary to make these places safe 24 hours a day," Mr. Wright-Neville said.

Indonesian authorities blame the Bali attack on Jemaah Islamiyah, a regional network of Islamic radicals with links to the worldwide al-Qaida terrorist organization. More than 30 people have been arrested in connection with the Bali attack.

Although the Indonesian police have not yet said who they think is responsible for Tuesday's attack in Jakarta, officials have noted there are similarities to the Bali attack.

Rohan Gunaratna, a terrorism expert and author of the book Inside al-Qaida, said Jemaah Islamiyah is the only group in the region with the expertise to pull off the hotel attack. He said it appears to be linked to the coming verdicts in the first trials of Bali bombing suspects.

"The timing of the attack is very significant with regard to the developments in Indonesia, where the trials of the Bali suspects are coming to a conclusion. And the sentencing of Amrozi will take place Thursday, who is a significant player in the Bali bombing," Mr. Gunaratna said. Indonesian authorities had tightened security at key points after the Bali attack. Reports said police had discovered a document last month that listed the Marriott hotel in Jakarta as a possible terrorist target. "Certainly the Indonesian authorities knew they were planning an operation in Jakarta," Mr. Gunaratna said.

The Indonesian police said they had increased security around the hotel before the attack. But Mr. Wright-Neville, now at the Global Terrorism Research Unit at Monash University, said security resources may have already been strained to the limit. Impoverished Indonesia struggles just to pay its police and military forces, and the additional security costs since the October Bali attack have been an burden.

"It's possible that the Indonesian authorities thought that this might have been disinformation. Or it's possible that their resources were simply so stretched that they couldn't put the security needed on all the places that were mentioned as a possible attack," he explained.

The problem is common in much of the region. In the Philippines, where communist insurgents and at least two Islamic militant groups have been responsible for bombings and attacks on civilian areas, police are often outgunned. It does not help that both Indonesia and the Philippines are vast archipelagos, with remote islands, and thick, mountainous jungles where terrorists can hide.

In Indonesia, authorities are bracing for more trouble. Many terrorism experts think that harsh sentences against the Bali bombing suspects - such as the death penalty or life imprisonment - could spark additional attacks from angry militants.