pl/pgsql trigger: syntax error at or near "ELSEIF"

Hello, what is the parser trying to tell me? (7.4.2 if it matters)

test=# CREATE OR REPLACE FUNCTION SYNC_COUPLECOUNT()
test-# RETURNS TRIGGER
test-# AS '
test'# BEGIN
test'# IF TG_OP = ''INSERT'' THEN
test'# UPDATE _calls
test'# SET
test'# realcouplecount = realcouplecount + 1
test'# WHERE
test'# id = NEW.callid;
test'# ELSEIF TG_OP = ''DELETE'' THEN
test'# UPDATE _calls
test'# SET
test'# realcouplecount = realcouplecount - 1
test'# WHERE
test'# id = NEW.callid;
test'# END IF;
test'# RETURN NEW;
test'# END;
test'# '
test-# LANGUAGE plpgsql;
CREATE FUNCTION
test=# CREATE TRIGGER triginsdel
test-# AFTER INSERT OR DELETE ON _couples
test-# FOR EACH ROW EXECUTE PROCEDURE SYNC_COUPLECOUNT();
CREATE TRIGGER
test=# insert into _couples (id, callid) values (get_next_coupleid(), 1);
ERROR: syntax error at or near "ELSEIF" at character 1
CONTEXT: PL/pgSQL function "sync_couplecount" line 8 at SQL statement

On a related note: if I replace NEW with OLD in the second UPDATE (in the
ELSEIF branch), I get:

test=# insert into _couples (id, callid) values (get_next_coupleid(), 1);
ERROR: record "old" is not assigned yet
DETAIL: The tuple structure of a not-yet-assigned record is indeterminate.
CONTEXT: PL/pgSQL function "sync_couplecount" line 8 at SQL statement

What's wrong with that?

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