Philippine politician Salvador Laurel, a leading candidate hoping to oppose President Ferdinand Marcos in elections called for January, returned home today to an enthusiastic welcome by 5,000 supporters.

Laurel asked Marcos, whom he has accused of election fraud, to ensure a free and fair election as the only peaceful way to bring about change. In comments directed at the ruling party, he warned: "You will have to kill us in order to cheat us. This is no ordinary election. This is an election where everything will be risked -- life, liberty and honor. This is the price of freedom."

Laurel said that if he is elected he will jail those found guilty of corruption.

Asked specifically whether he would bring charges against Marcos, Laurel declared, "We will give Mr. Marcos what he has not given the people of the Philippines -- justice and due process of law."

Laurel reiterated that if he came to power he would respect the current agreement on U.S. military bases in the Philippines, which expires in 1991. After that, he said, the arrangement must be renegotiated and the results subjected to a plebiscite.

Laurel, who was in the United States when Marcos announced the election, went home from the airport in a festive motorcade. In a crowded press conference, he pledged to support whoever is chosen as the candidate to oppose Marcos by a National Unification Committee of the opposition groups.

The jockeying for the presidential nomination is reaching a climax this week with the gathering support for another favorite, Corazon Aquino, widow of slain opposition leader Benigno Aquino Jr.

Laurel who heads Unido, the largest opposition coalition of eight parties, said that he will meet with Aquino tonight to see if she is really interested in running. He said: "At this point it is not something for Cory Aquino and me to decide. The matter will require the consultation of all other leaders in the democratic oposition."

Aquino was at the airport to meet Laurel.