I think my site is under attack

This morning I woke up and noticed that you had more than 20 attempts to enter the wp-admin.php, I use WP plugins-Security and could block access to wp-admin, so can not be accessed, you must have a secret key..

the problem is that after a few hours the system sent me a message.

A lockdown event has occurred due to too many failed login attempts or invalid username:
Username: админ
IP Address: 77.247.168.251

IP Range: 77.247.168.*

and 4pages more :
46.118.137.*
0 Administrator 2013-10-11 13:03:38
91.237.164.*
0 user 2013-10-11 13:02:36
109.254.47.*
0 adm 2013-10-11 13:02:04
178.125.16.*
0 админ 2013-10-11 13:01:35
37.75.105.*
0 Administrator 2013-10-11 13:01:21
178.151.70.*
0 adm 2013-10-11 13:00:47
94.178.55.*
0 test 2013-10-11 13:00:31
94.178.55.*
0 test 2013-10-11 13:00:31
46.201.147.*
0 adm 2013-10-11 13:00:09
46.251.82.*
0 support 2013-10-11 13:00:00
177.193.10.*
0 adm 2013-10-11 12:59:12
203.170.189.*
0 user 2013-10-11 12:59:10
77.91.188.*
0 admin 2013-10-11 12:58:56
178.127.214.*
0 admin 2013-10-11 12:58:41
178.123.81.*
0 user2 2013-10-11 12:58:24
95.133.139.*
0 user 2013-10-11 12:57:52
93.127.88.*
0 test 2013-10-11 12:57:49
219.92.9.*
0 test 2013-10-11 12:57:36
95.27.74.*
Delete
0 adm 2013-10-11 12:57:23
95.27.74.*
0 adm 2013-10-11 12:57:23

What means this, that still trying to get in?
Someone can help plz!