WASHINGTON (AP) _ President Bush warmly welcomed the election Sunday of Rene Mouawad as president of Lebanon and urged all Lebanese to back his efforts to end the 14- year civil war.

The State Department also issued a congratulatory statement that singled out for criticism Christian army commander Gen. Michel Aoun, who had tried to block the session of the Lebanese parliament that elected Mouawad.

''We call upon Gen. Aoun and the Armed Forces to respect the results of parliament's action,'' said State Department spokeswoman Nancy Beck, reading a written statement.

At the White House, presidential spokesman Marlin Fitzwater said Bush ''welcomes the election of Rene Mouawad ... The president also commends Lebanon's parliament for its ratification of the national reconciliation charter.''

The State Department said that ''we extend to President Mouawad our sincere congratulations and best wishes ... We ask all parties to refrain from violence and intimidation and aid President Mouawad in reunifying Lebanon.''

To elect Mouawad, parliament met beyond the range of Aoun's artillery at Kleiat, in Syrian-policed north Lebanon. The parliament also ratified a peace plan brokered by the Arab League last month in Taif, Saudi Arabia.

The State Department statement said: ''General Aoun, with his confrontational tactics and threats of partition, does a disservice to the state and people he claims to defend.

''We believe that the overwhelming majority of Lebanese wish for an end to 14 years of war and a restoration of Lebanon's unity, independence and sovereignty.

''The election of President Mouawad and the ratification of the Taif agreement are the first steps toward achieving those goals as well as the withdrawal of all foreign forces.''

Aoun had threatened to shell parliament when it initially planned to meet in Beirut on Saturday to ratify the Taif accord.

The peace plan shifts political power to the Moslem majority from the Christians, who were believed to be in the majority when the existing political system was devised in the 1940s. Aoun opposes the accord because it has no fixed schedule for a total withdrawal of the estimated 40,000 Syrian troops backing Moslem forces.

Mouawad is a Maronite Catholic. Parliament also re-elected house speaker Hussein Husseini, a Shiite Moslem who has held the post since 1984.