Taiwan stepped up pressure on Manila Tuesday, saying it would conduct a naval drill in waters near the Philippines if Manila did not officially apologize for the killing of a Taiwanese fisherman.

Taiwan has demanded the Philippines apologize by midnight Tuesday (1600 GMT) over the killing of the 65-year-old fisherman by coastguards last week or face a potential freeze in sending workers to the island.

Former President Joseph Estrada was proclaimed Tuesday as the new mayor of the Philippine capital, his first elected post since he was ousted in an anti-corruption revolt 12 years ago.

In other partial results from Monday's congressional and local elections, nine senatorial candidates backed by President Benigno Aquino III took an early lead against three candidates backed by an opposition coalition. About half the votes have been reported so far, and if the trend continues, the wins will ensure congressional support for Aquino's remaining three years in office.

Philippine President Benigno Aquino called for calm Monday amid an escalating dispute with Taiwan over the death of a Taiwanese fisherman in an incident involving the Filipino coastguard.

Aquino said Manila's de facto embassy in Taiwan was in talks with Taiwanese foreign ministry officials and had assured them an investigation was being carried out into last week's incident in which the fisherman was shot dead.

The Philippines held elections Monday seen as crucial for President Benigno Aquino's bold reform agenda, as deadly violence and graft-tainted candidates underlined the nation's deep-rooted problems.

Aquino has called for the mid-term polls, in which thousands of local leaders plus national legislators will be elected, to be a referendum on his efforts to transform a corrupt political system and an underperforming economy.

Syrian rebels Sunday freed four Filipino peacekeepers five days after seizing them at an observation post in the Golan Heights, the Philippine military's chief spokesman said, as the U.N. said Qatar played a key role in negotiating their release.

"They have been released. They are now in the custody of the commander of the Philippine battalion in the Golan Heights," Brigadier General Domingo Tutaan told Agence France Presse.

Rebels in Syria's Golan have posted a new video online showing four Filipino U.N. peacekeepers they abducted earlier this week, with the men apparently unharmed, restating that their action aimed to protect the soldiers.

"The Yarmuk Martyrs Brigade's leadership announces it is responsible for saving four members of the U.N. force from an area of battles pitting (rebel) brigade members against criminals from gangs loyal to (President Bashar) Assad," an unnamed spokesman said in the video.

The Philippines on Wednesday banned people from carrying large amounts of cash and buying alcohol in controversial efforts to curb rampant vote-buying and violence before elections next week.

The shock money ban means banks are not allowed to hand over more than 100,000 pesos ($2,400) to customers until after Monday's mid-term elections, the Commission on Elections announced.

An armed group on Tuesday abducted four U.N. peacekeepers from the Philippines in the Golan Heights, which has been hit by mounting spillover from the Syrian civil war, the United Nations said.

The four were patrolling near the Al Jamlah locality in the ceasefire zone between Israel and Syria where 21 Filipino peacekeepers were seized by Syrian rebels in March, said a U.N. peacekeeping spokeswoman, Josephine Guerrero.

Five people are feared dead after one of the Philippines' most active volcanoes spewed a giant ash cloud on Tuesday, with foreign tourists on its slopes during the eruption, authorities said.

National Disaster Risk Reduction and Management Council chief Eduardo del Rosario said local officials reported that up to 20 climbers and guides, including foreigners, were on Mount Mayon when it erupted.

Communist insurgents attacked a major mining company in the central Philippines, killing five soldiers and burning equipment and buildings the military said Saturday, as hopes for peace dimmed further.

The attack came just days after the chief government peace negotiator said talks with communist rebels had collapsed, ending hopes of achieving peace after a 44-year insurgency before President Benigno Aquino's term ends in 2016.