The calls followed a parliamentary session during which Lahoud, in a message read by the speaker, urged lawmakers to draw up an election law acceptable to all Lebanon's disparate factions for polls that are supposed to start on 29 May.
Opposition lawmakers, led by Druze leader Walid Jumblat, accused Lahoud of presiding over security agencies that they blamed for Friday night's bombing in the Christian port city Jounieh, 15km north of Beirut.
Police said the two dozen injuries, half from flying glass, were caused by the blast from an estimated 25kg bomb placed in a suitcase under a car on the street.
Lahoud has condemned the latest attack, which followed bombings in March and April in Christian districts and strongholds of opponents of Syria's influence that killed three people and injured 24.
Jumblat (R) accused Lahoud of
stirring up sectarianism
The president linked the Jounieh blast to political developments expected on Saturday, apparently referring to parliament's election law discussion and the imminent return of Lebanon's most prominent anti-Syrian politician, Michel Aoun, who left Paris for Beirut after 14 years' exile in France.
Before leaving Paris, Aoun said he was filled with emotions on returning to his homeland. His supporters planned a mass welcome in downtown Beirut.
Outside the legislature, Jumblat launched a scathing attack against Lahoud, an ally of Syria who many in Lebanon have linked to the 14 February assassination of former prime minister Rafiq al-Hariri.
"The head of the security apparatus cannot stay," Jumblat said in reference to the president.
"There needs to be a complete reform."
Jumblat said he had warned Christian opposition partners to force Lahoud, a Christian, to resign, but his call had been previously rejected. "He (Lahoud) stayed and now he is playing with us by outbidding on sectarian issues and by bombs," Jumblat alleged.
Lahoud's term was extended in
Opposition lawmakers from across Lebanon's religious divides backed Jumblat's call.
"We consider him (Jumblat) a principal partner in the building of a new state, which should be bringing down Emile Lahoud after the parliamentary elections because he is the head of the security regime," said Christian lawmaker Nayla Muawad, widow of President Rene Muawad who was slain in 1989.
Lahoud face trial?
Shia Muslim opposition lawmaker Basim Sabai said Lahoud
"must bear the political and moral responsibility" for Lebanon's crisis. Walid Eido, a Sunni Muslim opposition legislator, also said the president should resign and face trial.
Parliament cannot remove the president, who must resign
out of his own will.
In September, the parliament extended Lahoud's presidential term under pressure from Lebanon's then political masters, Syria. That was before thousands of Syrian forces withdrew from Lebanon in the light of intense UN and US pressure.
Many Lebanese opposition members blame Lahoud's three-year for precipitating the crisis, which reached its climax with the killing of al-Hariri, Lahoud's political rival.
Security elements remain
The opposition blames pro-Syrian Lebanese politicians and Damascus for the attack, but both the Lebanese and Syrian governments deny involvement.
Since al-Hariri's death, Lebanese Muslims and Christians have united in mass protests against Syria's influence in the country.
A new Lebanese government was installed last month, but the opposition complains pro-Syrian security elements still wield influence despite the removal of pro-Syrian Lebanese security chiefs.
Earlier on Saturday, new Interior Minister Hasan Sabai said Lebanese wanting national unity would not be cowed by the Jounieh bombing.
"I say to those criminals that they will not stop the Lebanese people from forging ahead with the journey that they started in 14 March," he said, referring to a huge anti-Syrian demonstration that called for an end to 29 years of Syrian dominance.